To see the other types of publications on this topic, follow the link: Calculo de sequentes.
Journal articles on the topic 'Calculo de sequentes'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 26 journal articles for your research on the topic 'Calculo de sequentes.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Kuznets, Roman, and Björn Lellmann. "Interpolation for intermediate logics via injective nested sequents." Journal of Logic and Computation 31, no. 3 (April 2021): 797–831. http://dx.doi.org/10.1093/logcom/exab015.
Full textAbstract:
Abstract We introduce a novel, semantically inspired method of constructing nested sequent calculi for propositional intermediate logics. Applying recently developed methods for proving Craig interpolation to these nested sequent calculi, we obtain constructive proofs of the interpolation property for most non-trivial interpolable intermediate logics, as well as Lyndon interpolation for Gödel logic. Finally, we provide a prototype implementation combining proof search and countermodel construction.
2
Alonderis, Romas, and Haroldas Giedra. "A derivation-loop method for temporal logic." Lietuvos matematikos rinkinys 60 (November 12, 2019): 1–6. http://dx.doi.org/10.15388/lmr.a.2019.14953.
Full textAbstract:
Various types of calculi (Hilbert, Gentzen sequent, resolution calculi, tableaux) for propositional linear temporal logic (PLTL) have been considered in the literature. Cutfree Gentzen-type sequent calculi are convenient tools for backward proof-search search of formulas and sequents. In this paper we present a cut-free Gentzen type sequent calculus for PLTL with the operator
3
Negri, Sara, and Eugenio Orlandelli. "Proof theory for quantified monotone modal logics." Logic Journal of the IGPL 27, no. 4 (May 24, 2019): 478–506. http://dx.doi.org/10.1093/jigpal/jzz015.
Full textAbstract:
Abstract This paper provides a proof-theoretic study of quantified non-normal modal logics (NNML). It introduces labelled sequent calculi based on neighbourhood semantics for the first-order extension, with both varying and constant domains, of monotone NNML, and studies the role of the Barcan formulas in these calculi. It will be shown that the calculi introduced have good structural properties: invertibility of the rules, height-preserving admissibility of weakening and contraction and syntactic cut elimination. It will also be shown that each of the calculi introduced is sound and complete with respect to the appropriate class of neighbourhood frames. In particular, the completeness proof constructs a formal derivation for derivable sequents and a countermodel for non-derivable ones, and gives a semantic proof of the admissibility of cut.
4
VAN BAKEL, STEFFEN, and PIERRE LESCANNE. "Computation with classical sequents." Mathematical Structures in Computer Science 18, no. 3 (June 2008): 555–609. http://dx.doi.org/10.1017/s0960129508006762.
Full textAbstract:
$\X$is an untyped continuation-style formal language with a typed subset that provides a Curry–Howard isomorphism for a sequent calculus for implicative classical logic.$\X$can also be viewed as a language for describing nets by composition of basic components connected by wires. These features make${\X}$an expressive platform on which many different (applicative) programming paradigms can be mapped. In this paper we will present the syntax and reduction rules for$\X$; in order to demonstrate its expressive power, we will show how elaborate calculi can be embedded, such as the λ-calculus, Bloo and Rose's calculus of explicit substitutions λx, Parigot's λμ and Curien and Herbelin's$\lmmt$.${\X}$was first presented in Lengrand (2003), where it was called the λξ-calculus. It can be seen as the pure untyped computational content of the reduction system for the implicative classical sequent calculus of Urban (2000).
5
VESTERGAARD, RENÉ, and JOE WELLS. "Cut rules and explicit substitutions." Mathematical Structures in Computer Science 11, no. 1 (February 2001): 131–68. http://dx.doi.org/10.1017/s0960129500003273.
Full textAbstract:
We introduce a method to associate calculi of proof terms and rewrite rules with cut elimination procedures for logical deduction systems (i.e., Gentzen-style sequent calculi) in the case of intuitionistic logic. We illustrate this method using two different versions of the cut rule for a variant of the intuitionistic fragment of Kleene's logical deduction system G3.Our systems are in fact calculi of explicit substitution, where the cut rule introduces an explicit substitution and the left-→ rule introduces a binding of the result of a function application. Cut propagation steps of cut elimination correspond to propagation of explicit substitutions, and propagation of weakening (to eliminate it) corresponds to propagation of index-updating operations. We prove various subject reduction, termination, and confluence properties for our calculi.Our calculi improve on some earlier calculi for logical deduction systems in a number of ways. By using de Bruijn indices, our calculi qualify as first-order term rewriting systems (TRS's), allowing us to use correctly certain results for TRS's about termination. Unlike in some other calculi, each of our calculi has only one cut rule and we do not need unusual features of sequents.We show that the substitution and index-updating mechanisms of our calculi work the same way as the substitution and index-updating mechanisms of Kamareddine and Ríos' λs and λt, two well-known systems of explicit substitution for the standard λ-calculus. By a change in the format of sequents, we obtain similar results for a known λ-calculus with variables and explicit substitutions, Rose's λbxgc.
6
AGUILERA, JUAN P., and MATTHIAS BAAZ. "UNSOUND INFERENCES MAKE PROOFS SHORTER." Journal of Symbolic Logic 84, no. 1 (March 2019): 102–22. http://dx.doi.org/10.1017/jsl.2018.51.
Full textAbstract:
AbstractWe give examples of calculi that extend Gentzen’s sequent calculusLKby unsound quantifier inferences in such a way that (i) derivations lead only to true sequents, and (ii) proofs therein are nonelementarily shorter thanLK-proofs.
7
ZORZI, MARGHERITA. "On quantum lambda calculi: a foundational perspective." Mathematical Structures in Computer Science 26, no. 7 (November 17, 2014): 1107–95. http://dx.doi.org/10.1017/s0960129514000425.
Full textAbstract:
In this paper, we propose an approach to quantum λ-calculi. The ‘quantum data-classical control’ paradigm is considered. Starting from a measurement-free untyped quantum λ-calculus calledQ, we will study standard properties such as confluence and subject reduction, and some good quantum properties. We will focus on the expressive power, analysing the relationship with other quantum computational models. Successively, we will add an explicit measurement operator toQ. On the resulting calculus, calledQ*, we will propose a complete study of reduction sequences regardless of their finiteness, proving confluence results. Moreover, since the stronger motivation behind quantum computing is the research of new results in computational complexity, we will also propose a calculus which captures the three classes of quantum polytime complexity, showing an ICC-like approach in the quantum setting.
8
CHEMOUIL, DAVID. "An insertion operator preserving infinite reduction sequences." Mathematical Structures in Computer Science 18, no. 4 (August 2008): 693–728. http://dx.doi.org/10.1017/s0960129508006816.
Full textAbstract:
A common way to show the termination of the union of two abstract reduction systems, provided both systems terminate, is to prove that they enjoy a specific property (some sort of ‘commutation’ for instance). This specific property is actually used to show that, for the union not to terminate, one of the systems must itself be non-terminating, which leads to a contradiction. Unfortunately, the property may be impossible to prove because some of the objects that are reduced do not enjoy an adequate form.Hence the purpose of this paper is threefold:–First, it introduces an operator enabling us to insert a reduction step on such an object, and therefore to change its shape, while still preserving the ability to use the property. Of course, some new properties will need to be verified.–Second, as an instance of our technique, the operator is applied to relax a well-known lemma stating the termination of the union of two termination abstract reduction systems.–Finally, this lemma is applied in a peculiar and then in a more general way to show the termination of some lambda calculi with inductive types augmented with specific reductions dealing with:(i)copies of inductive types;(ii)the representation of symmetric groups.
9
Rinaldi, Anne-Marie. "Ostensifs et calcul soustractif à l’école élémentaireOstensives and subtractive calculus at school." Educação Matemática Pesquisa : Revista do Programa de Estudos Pós-Graduados em Educação Matemática 22, no. 4 (September 15, 2020): 756–71. http://dx.doi.org/10.23925/1983-3156.2020v22i4p756-771.
Full textAbstract:
RésuméMon travail de thèse dans le cadre de la théorie anthropologique du didactique m’a permis de construire une organisation mathématique de référence autour du calcul soustractif et d’élaborer une ingénierie pour le CE2, en cherchant à rester assez proche des pratiques de l’enseignement ordinaire. L’évolution des productions des élèves et des discours des enseignants sur un ensemble de séquences permet de questionner l’usage d’ostensifs tels que les écritures arithmétiques et les schémas avec la droite numérique dans le but de décrire, valider et évaluer un ensemble de techniques de calcul mental.Mots clés : Ostensif, Techniques de calcul mental.AbstractMy thesis work within the framework of the Anthropological Theory of Didactics allowed me to build a mathematical organization of reference around the subtractive calculation and to elaborate an engineering for the CE2, trying to remain rather close to the practices of the teaching ordinary. The evolution of students 'productions and teachers' speeches on a set of sequences makes it possible to question the use of ostensives such as arithmetic writings and diagrams with the number line in order to describe, validate and evaluate a set of techniques of mental calculation.Keywords: Ostensive, Techniques of mental calculation.
10
Rinaldi, Anne-Marie. "Ostensifs et calcul soustractif à l’école élémentaireOstensives and subtractive calculus at school." Educação Matemática Pesquisa : Revista do Programa de Estudos Pós-Graduados em Educação Matemática 22, no. 4 (September 15, 2020): 756–71. http://dx.doi.org/10.23925/1983-3156.2020v22i4p756-771.
Full textAbstract:
RésuméMon travail de thèse dans le cadre de la théorie anthropologique du didactique m’a permis de construire une organisation mathématique de référence autour du calcul soustractif et d’élaborer une ingénierie pour le CE2, en cherchant à rester assez proche des pratiques de l’enseignement ordinaire. L’évolution des productions des élèves et des discours des enseignants sur un ensemble de séquences permet de questionner l’usage d’ostensifs tels que les écritures arithmétiques et les schémas avec la droite numérique dans le but de décrire, valider et évaluer un ensemble de techniques de calcul mental.Mots clés : Ostensif, Techniques de calcul mental.AbstractMy thesis work within the framework of the Anthropological Theory of Didactics allowed me to build a mathematical organization of reference around the subtractive calculation and to elaborate an engineering for the CE2, trying to remain rather close to the practices of the teaching ordinary. The evolution of students 'productions and teachers' speeches on a set of sequences makes it possible to question the use of ostensives such as arithmetic writings and diagrams with the number line in order to describe, validate and evaluate a set of techniques of mental calculation.Keywords: Ostensive, Techniques of mental calculation.
11
Van Benthem, Johan. "Logic as Programming." Fundamenta Informaticae 17, no. 4 (November 1, 1992): 285–317. http://dx.doi.org/10.3233/fi-1992-17402.
Full textAbstract:
Starting from a general dynamic analysis of reasoning and programming, we develop two main dynamic perspectives upon logic programming. First, the standard fixed point semantics for Horn clause programs naturally supports imperative programming styles. Next, we provide axiomatizations for Prolog-type inference engines using calculi of sequents employing modified versions of standard structural rules such as monotonicity or permutation. Finally, we discuss the implications of all this for a broader enterprise of ‘abstract proof theory’.
12
Henglein, Fritz, and Harry G. Mairson. "The complexity of type inference for higher-order typed lambda calculi." Journal of Functional Programming 4, no. 4 (October 1994): 435–77. http://dx.doi.org/10.1017/s0956796800001143.
Full textAbstract:
AbstractWe analyse the computational complexity of type inference for untyped λ-terms in the second-order polymorphic typed λ-calculus (F2) invented by Girard and Reynolds, as well as higher-order extensions F3, F4, …, Fω proposed by Girard. We prove that recognising the F2-typable terms requires exponential time, and for Fω the problem is non-elementary. We show as well a sequence of lower bounds on recognising the Fk-typable terms, where the bound for Fk+1 is exponentially larger than that for Fk.The lower bounds are based on generic simulation of Turing Machines, where computation is simulated at the expression and type level simultaneously. Non-accepting computations are mapped to non-normalising reduction sequences, and hence non-typable terms. The accepting computations are mapped to typable terms, where higher-order types encode reduction sequences, and first-order types encode the entire computation as a circuit, based on a unification simulation of Boolean logic. A primary technical tool in this reduction is the composition of polymorphic functions having different domains and ranges.These results are the first nontrivial lower bounds on type inference for the Girard/Reynolds system as well as its higher-order extensions. We hope that the analysis provides important combinatorial insights which will prove useful in the ultimate resolution of the complexity of the type inference problem.
13
Dyckhoff, Roy. "Contraction-free sequent calculi for intuitionistic logic." Journal of Symbolic Logic 57, no. 3 (September 1992): 795–807. http://dx.doi.org/10.2307/2275431.
Full textAbstract:
Gentzen's sequent calculus LJ, and its variants such as G3 [21], are (as is well known) convenient as a basis for automating proof search for IPC (intuitionistic propositional calculus). But a problem arises: that of detecting loops, arising from the use (in reverse) of the rule ⊃⇒ for implication introduction on the left. We describe below an equivalent calculus, yet another variant on these systems, where the problem no longer arises: this gives a simple but effective decision procedure for IPC.The underlying method can be traced back forty years to Vorob′ev [33], [34]. It has been rediscovered recently by several authors (the present author in August 1990, Hudelmaier [18], [19], Paulson [27], and Lincoln et al. [23]). Since the main idea is not plainly apparent in Vorob′ev's work, and there are mathematical applications [28], it is desirable to have a simple proof. We present such a proof, exploiting the Dershowtiz-Manna theorem [4] on multiset orderings.Consider the task of constructing proofs in Gentzen's sequent calculus LJ of intuitionistic sequents Γ⇒ G, where Γ is a set of assumption formulae and G is a formula (in the language of zero-order logic, using the nullary constant f [absurdity], the unary constant ¬ [negation, with ¬A =defA ⊃ f] and the binary constants &, ∨, and ⊃ [conjunction, disjunction, and implication respectively]). By the Hauptsatz [15], there is an apparently simple algorithm which breaks up the sequent, growing the proof tree until one reaches axioms (of the form Γ⇒ A where A is in Γ), or can make no further progress and must backtrack or even abandon the search. (Gentzen's argument in fact was to use the subformula property derived from the Hauptsatz to limit the size of the search tree. Došen [5] improves on this argument.)
14
Konikowska, Beata, Andrzej Tarlecki, and Andrzej Blikle. "A Three-Valued Logic for Software Specification and Validation. Tertium tamen datur." Fundamenta Informaticae 14, no. 4 (April 1, 1991): 411–53. http://dx.doi.org/10.3233/fi-1991-14403.
Full textAbstract:
Different calculi of partial or three-valued predicates have been used and studied by several authors in the context of software specification, development and validation. This paper offers a critical survey on the development of three-valued logics based on such calculi. In the first part of the paper we review two three-valued predicate calculi, based on, respectively, McCarthy’s and Kleene’s propositional connectives and quantifiers, and point out that in a three-valued logic one should distinguish between two notions of validity: strong validity (always true) and weak validity (never false). We define in model-theoretic terms a number of consequence relations for three-valued logics. Each of them is determined by the choice of the underlying predicate calculus and of the weak or strong validity of axioms and of theorems. We discuss mutual relationships between consequence relations defined in such a way and study some of their basic properties. The second part of the paper is devoted to the development of a formal deductive system of inference rules for a three-valued logic. We use the method of semantic tableaux (slightly modified to deal with three-valued formulas) to develop a Gentzen-style system of inference rules for deriving valid sequents, from which we then derive a sound and complete system of natural deduction rules. We have chosen to study the consequence relation determined by the predicate calculus with McCarthy’s propositional connectives and Kleene’s quantifiers and by the strong interpretation of both axioms and theorems. Although we find this choice appropriate for applications in the area of software specification, verification and development, we regard this logic merely as an example and use it to present some general techniques of developing a sequent calculus and a natural deduction system for a three-valued logic. We also discuss the extension of this logic by a non-monotone is-true predicate.
15
GORÉ, RAJEEV, and REVANTHA RAMANAYAKE. "VALENTINI’S CUT-ELIMINATION FOR PROVABILITY LOGIC RESOLVED." Review of Symbolic Logic 5, no. 2 (March 6, 2012): 212–38. http://dx.doi.org/10.1017/s1755020311000323.
Full textAbstract:
Valentini (1983) has presented a proof of cut-elimination for provability logic GL for a sequent calculus using sequents built from sets as opposed to multisets, thus avoiding an explicit contraction rule. From a formal point of view, it is more syntactic and satisfying to explicitly identify the applications of the contraction rule that are ‘hidden’ in proofs of cut-elimination for such sequent calculi. There is often an underlying assumption that the move to a proof of cut-elimination for sequents built from multisets is straightforward. Recently, however, it has been claimed that Valentini’s arguments to eliminate cut do not terminate when applied to a multiset formulation of the calculus with an explicit rule of contraction. The claim has led to much confusion and various authors have sought new proofs of cut-elimination for GL in a multiset setting.Here we refute this claim by placing Valentini’s arguments in a formal setting and proving cut-elimination for sequents built from multisets. The use of sequents built from multisets enables us to accurately account for the interplay between the weakening and contraction rules. Furthermore, Valentini’s original proof relies on a novel induction parameter called “width” which is computed ‘globally’. It is difficult to verify the correctness of his induction argument based on “width.” In our formulation however, verification of the induction argument is straightforward. Finally, the multiset setting also introduces a new complication in the case of contractions above cut when the cut-formula is boxed. We deal with this using a new transformation based on Valentini’s original arguments.Finally, we discuss the possibility of adapting this cut-elimination procedure to other logics axiomatizable by formulae of a syntactically similar form to the GL axiom.
16
SADRZADEH, MEHRNOOSH, and ROY DYCKHOFF. "POSITIVE LOGIC WITH ADJOINT MODALITIES: PROOF THEORY, SEMANTICS, AND REASONING ABOUT INFORMATION." Review of Symbolic Logic 3, no. 3 (August 12, 2010): 351–73. http://dx.doi.org/10.1017/s1755020310000134.
Full textAbstract:
We consider a simple modal logic whose nonmodal part has conjunction and disjunction as connectives and whose modalities come in adjoint pairs, but are not in general closure operators. Despite absence of negation and implication, and of axioms corresponding to the characteristic axioms of (e.g.) T, S4, and S5, such logics are useful, as shown in previous work by Baltag, Coecke, and the first author, for encoding and reasoning about information and misinformation in multiagent systems. For the propositional-only fragment of such a dynamic epistemic logic, we present an algebraic semantics, using lattices with agent-indexed families of adjoint pairs of operators, and a cut-free sequent calculus. The calculus exploits operators on sequents, in the style of “nested” or “tree-sequent” calculi; cut-admissibility is shown by constructive syntactic methods. The applicability of the logic is illustrated by reasoning about the muddy children puzzle, for which the calculus is augmented with extra rules to express the facts of the muddy children scenario.
17
INDRZEJCZAK, ANDRZEJ. "LINEAR TIME IN HYPERSEQUENT FRAMEWORK." Bulletin of Symbolic Logic 22, no. 1 (March 2016): 121–44. http://dx.doi.org/10.1017/bsl.2016.2.
Full textAbstract:
AbstractHypersequent calculus (HC), developed by A. Avron, is one of the most interesting proof systems suitable for nonclassical logics. Although HC has rather simple form, it increases significantly the expressive power of standard sequent calculi (SC). In particular, HC proved to be very useful in the field of proof theory of various nonclassical logics. It may seem surprising that it was not applied to temporal logics so far. In what follows, we discuss different approaches to formalization of logics of linear frames and provide a cut-free HC formalization ofKt4.3, the minimal temporal logic of linear frames, and some of its extensions. The novelty of our approach is that hypersequents are defined not as finite (multi)sets but as finite lists of ordinary sequents. Such a solution allows both linearity of time flow, and symmetry of past and future, to be incorporated by means of six temporal rules (three for future-necessity and three dual rules for past-necessity). Extensions of the basic calculus with simple structural rules cover logics of serial and dense frames. Completeness is proved by Schütte/Hintikka-style argument using models built from saturated hypersequents.
18
BAHR, PATRICK. "Convergence in infinitary term graph rewriting systems is simple." Mathematical Structures in Computer Science 28, no. 8 (August 9, 2018): 1363–414. http://dx.doi.org/10.1017/s0960129518000166.
Full textAbstract:
Term graph rewriting provides a formalism for implementing term rewriting in an efficient manner by emulating duplication via sharing. Infinitary term rewriting has been introduced to study infinite term reduction sequences. Such infinite reductions can be used to model non-strict evaluation. In this paper, we unify term graph rewriting and infinitary term rewriting thereby addressing both components of lazy evaluation: non-strictness and sharing. In contrast to previous attempts to formalise infinitary term graph rewriting, our approach is based on a simple and natural generalisation of the modes of convergence of infinitary term rewriting. We show that this new approach is better suited for infinitary term graph rewriting as it is simpler and more general. The latter is demonstrated by the fact that our notions of convergence give rise to two independent canonical and exhaustive constructions of infinite term graphs from finite term graphs via metric and ideal completion. In addition, we show that our notions of convergence on term graphs are sound w.r.t. the ones employed in infinitary term rewriting in the sense that convergence is preserved by unravelling term graphs to terms. Moreover, the resulting infinitary term graph calculi provide a unified framework for both infinitary term rewriting and term graph rewriting, which makes it possible to study the correspondences between these two worlds more closely.
19
De Lima, Olivar A. L., and Hédison K. Sato. "APPLICATION OF FREQUENCY AND TIME DOMAIN INDUCED POLARIZATION – RESISTIVITY EFFECTS FOR EXPLORING AQUIFER AND HYDROCARBON RESERVOIRS IN BAHIA, BRAZIL." Brazilian Journal of Geophysics 37, no. 4 (December 1, 2019): 545. http://dx.doi.org/10.22564/rbgf.v37i4.2030.
Full textAbstract:
ABSTRACT. Two field surveys using the induced polarization (IP) – resistivity method, are presented as an effective tool to evaluate aquifer and hydrocarbon reservoirs at shallow depths. First, the electrochemical mechanisms responsible for generating IP effects in reservoir rocks are reviewed. Then, theoretical developments are proposed to reduce the inductive electromagnetic coupling from the underground IP effects, and to compute three fundamental electrical parameters, namely the apparent DC-resistivity, the apparent chargeability and relaxation time, both for frequency (FD) and time-domain (TD) data. These parameters are attributed to average representative volumes of the subsurface geology, which depends on the electrode array and its characteristic depth of investigation. The studied structure includes: an upper fresh-water sandstone aquifer of 60m average thickness; overlaying a 70m thick, prismatic sandstone oil-reservoir, sandwiched between shale sequences and laterally confined by intersecting normal faults. The data acquisitions were made using dipole-dipole electrode arrays, with lengths a of 50 and 100 m, and separations na, with n ranging from 1 to 12 (FD), and 1 to 6 (TD). The 2-D inverted pseudo-sections exhibit small distortions, attributed to differences in resolution, terrain effects and signal-to-noise ratios, but are consistent in outlining the following features: i) the detection of an upper resistive low-IP layer, representing a water-table aquifer; ii) a distinct electrical anomaly, related to the western bounding fault zone, depicted as a conductive chimney bordered by high resistive halos; iii) the separation of different geo-electrical units within the shale sequence sealing the reservoir; and iv) the delineation of the top of oil reservoir, defined by a slight increase in resistivity and by high IP values, at and above the oil reservoir.Keywords: electrical resistivity, induced polarization, aquifers, oil reservoirs.RESUMO. Levantamentos geofísicos usando resistividade e polarização induzida (PI) são apresentados como ferramenta eficaz para avaliar aquíferos e reservatórios petrolíferos em profundidades rasas. Primeiro, faz-se uma revisão dos mecanismos eletroquímicos geradores de PI em rochas reservatórios. Em seguida, propõem-se tratamentos teóricos para separar o acoplamento eletromagnético dos efeitos puros da PI subterrânea e calcular três parâmetros aparentes fundamentais: resistividade (ρ0,a), cargabilidade (mw,a) e tempo de relação (τ w,a), tanto no domínio da frequência (FD) quanto do tempo (TD). Esses parâmetros são atribuídos a centros volumétricos representativos da geologia, que dependem do arranjo de eletrodos e de suas profundidades de investigação. A estrutura estudada inclui: um aquífero arenoso superior, com 60m de espessura; sobreposto a um reservatório petrolífero prismático de arenitos, com 70m de espessura, intercalado entre sequências argilosas, e lateralmente confinado por falhas normais intercruzadas. Os dados foram adquiridos com arranjos dipolo-dipolo usando distâncias entre eletrodos de 50 e 100 m, e separações na, com n variando de 1 a 12 (FD) e 1 a 6 (TD). As seções 2-D invertidas exibem pequenas distorções, atribuídas a diferenças de resolução, efeitos de terreno e razão sinal-ruído, mas consistentes na identificação dos seguintes aspectos: (i) detecção de camada superior resistiva e baixo PI, representando o aquífero freático; (ii) anomalia elétrica relacionada à falha do limite ocidental, revelada como uma chaminé condutora com halos de maior resistividade; (iii) separação de duas unidades geoelétricas na sequência dos folhelhos selantes do reservatório; e (iv) delineamento do topo do reservatório de óleo, definido por um ligeiro aumento na resistividade e por altos valores de PI no e acima do reservatório.Palavras-chave: resistividade elétrica, polarização induzida, aquíferos, reservatórios.
20
Indrzejczak, Andrzej. "Rule-Generation Theorem and its Applications." Bulletin of the Section of Logic 47, no. 4 (December 30, 2018). http://dx.doi.org/10.18778/0138-0680.47.4.03.
Full textAbstract:
In several applications of sequent calculi going beyond pure logic, an introduction of suitably defined rules seems to be more profitable than addition of extra axiomatic sequents. A program of formalization of mathematical theories via rules of special sort was developed successfully by Negri and von Plato. In this paper a general theorem on possible ways of transforming axiomatic sequents into rules in sequent calculi is proved. We discuss its possible applications and provide some case studies for illustration.
21
French, Rohan. "Metasequents and Tetravaluations." Journal of Philosophical Logic, August 25, 2021. http://dx.doi.org/10.1007/s10992-021-09623-7.
Full textAbstract:
AbstractIn this paper we treat metasequents—objects which stand to sequents as sequents stand to formulas—as first class logical citizens. To this end we provide a metasequent calculus, a sequent calculus which allows us to directly manipulate metasequents. We show that the various metasequent calculi we consider are sound and complete w.r.t. appropriate classes of tetravaluations where validity is understood locally. Finally we use our metasequent calculus to give direct syntactic proofs of various collapse results, closing a problem left open in French (Ergo, 3(5), 113–131 2016).
22
Yazaki, Daishi. "Semantical Proof of Subformula Property for the Modal Logics K 4.3, KD 4.3, and S4.3." Bulletin of the Section of Logic 48, no. 4 (December 31, 2019). http://dx.doi.org/10.18778/0138-0680.48.4.01.
Full textAbstract:
The main purpose of this paper is to give alternative proofs of syntactical and semantical properties, i.e. the subformula property and the nite model property, of the sequent calculi for the modal logics K4.3, KD4.3, and S4.3. The application of the inference rules is said to be acceptable, if all the formulas in the upper sequents are subformula of the formulas in lower sequent. For some modal logics, Takano analyzed the relationships between the acceptable inference rules and semantical properties by constructing models. By using these relationships, he showed Kripke completeness and subformula property. However, his method is difficult to apply to inference rules for the sequent calculi for K4.3, KD4.3, and S4.3. Lookinglosely at Takano's proof, we nd that his method can be modied to construct nite models based on the sequent calculus for K4.3, if the calculus has (cut) and all the applications of the inference rules are acceptable. Similarly, we can apply our results to the calculi for KD4.3 and S4.3. This leads not only to Kripke completeness and subformula property, but also to finite model property of these logics simultaneously.
23
Hou, Qing-Hu, and Guoce Xin. "Constant term evaluation for summation of C-finite sequences." Discrete Mathematics & Theoretical Computer Science DMTCS Proceedings vol. AN,..., Proceedings (January 1, 2010). http://dx.doi.org/10.46298/dmtcs.2806.
Full textAbstract:
International audience Based on constant term evaluation, we present a new method to compute a closed form of the summation $∑_k=0^n-1 ∏_j=1^r F_j(a_jn+b_jk+c_j)$, where ${F_j(k)} are $C$-finite sequences and $a_j$ and $a_j+b_j$ are nonnegative integers. Our algorithm is much faster than that of Greene and Wilf. En s'appuyant sur l'évaluation de termes constants, nous présentons une nouvelle méthode pour calculer une forme close de la somme $∑_k=0^n-1 ∏_j=1^r F_j(a_jn+b_jk+c_j)$, où les ${F_j(k)}$ sont des suites C-finies, et où les $a_j$ et les $a_j+b_j$ sont des entiers positifs ou nuls. Notre algorithme est beaucoup plus rapide que celui de Greene et Wilf.
24
Indrzejczak, Andrzej. "Simple Decision Procedure for S5 in Standard Cut-Free Sequent Calculus." Bulletin of the Section of Logic 45, no. 2 (June 30, 2016). http://dx.doi.org/10.18778/0138-0680.45.2.05.
Full textAbstract:
In the paper a decision procedure for S5 is presented which uses a cut-free sequent calculus with additional rules allowing a reduction to normal modal forms. It utilizes the fact that in S5 every formula is equivalent to some 1-degree formula, i.e. a modally-flat formula with modal functors having only boolean formulas in its scope. In contrast to many sequent calculi (SC) for S5 the presented system does not introduce any extra devices. Thus it is a standard version of SC but with some additional simple rewrite rules. The procedure combines the proces of saturation of sequents with reduction of their elements to some normal modal form.
25
Le Trong, Binh, Bac Pham Thanh, Chau Tran Minh, and Khoan Le Trong. "Indications and techniques of mr urography." Journal of Medicine and Pharmacy, December 2020, 7–14. http://dx.doi.org/10.34071/jmp.2020.6.1.
Full textAbstract:
Magnetic Resonance Urography (MRU) provides a comprehensive assessment of both morphology and function of the urinary system by using various sequences of T1W, T2W, 2D and 3D. T1W and T2W 2D images are optimal to evaluate the morphology of the kidneys and the urinary tract. Fast gradient echo 3D T1W sequence with the use of fat saturation technique (Fatsat or Dixon sequences), gadolinium administration, diuretic maneuver, and maximum intensity projection allows visualization of the urinary tract similar to that of conventional intravenous urography. MRU is also helpful in investigating renal function based on the hemodynamic study of contrast medium. Recent data prove that MRU, except for the study of renal calculi, is not inferior to computed tomographic urography (CTU) in evaluating diseases of the urinary system such as neoplasm, malformation and obstruction. MRU is an alternative to CTU when CTU is contraindicated. This article aims to review the techniques of MRU to optimize visualization of the urinary system and their indications in daily practice. Key words: MRU, MR hydrography, MR dynamic
26
Barría Castro, José María, Linamar Antuaneth Caballero Vega, Javier Augusto Pimentel Sández, and Fernando Miguel Sucre Grimaldo. "Relación Entre El Coeficiente De Difusión Aparente y la celularidad. [Relación Entre El Coeficiente De Difusión Aparente yLa Celularidad De Gliomas en Centro de tercer nivel de Panamá]." Revista Médica de Panamá - ISSN 2412-642X 40, no. 1 (March 27, 2020). http://dx.doi.org/10.37980/im.journal.rmdp.2020823.
Full textAbstract:
<p>Resumen<br /><br />Introducción: Los gliomas son tumores malignos altamente celulares del sistema nervioso central. Su grado histológico preoperatorio es de utilidad en el manejo quirúrgico, por lo que la resonancia magnética con secuencias avanzadas intenta brindar mayor información tumoral. <br />Objetivo: Relacionar el coeficiente aparente de difusión (CAD) y celularidad de los gliomas de pacientes entre enero 2015 a diciembre 2017.</p><p><br />Metodología:Retrospectivamente se obtuvieron de archivos clínicos la edad, sexo, tipo, grado histológicoy sitio anatómico. Se calculó el CAD en 5mm2 en los estudios de resonancia magnética preoperatorias y se utilizó las laminillas para conteo de celularidad en 5mm2 digitalmente. Se utilizó análisis estadísticos descriptivos y coeficiente de correlación entre CDA con celularidad. Se utilizaron valores de p < 0.05 para significancia estadística.<br />Resultados: 46 casos fueron incluidos, 56.5% fueron hombres. El rango de 41-64 años fueron los más afectados. El glioblastoma fue el tipo histológico más frecuente (47.8%), así como los gliomas de alto grado (73.9%). El 95.7% fueron supratentoriales. La celularidad promedio fue de 3970 ± 2900 vs 2436 ± 948 núcleos/5mm2 (p = 0.13), con valores promedio de CDA mínimo de 0.813 x 10-3 ± 0.229 mm2/s vs 1.052 x 10-3 ± 0.196 mm2/s (p = 0.002), para los gliomas de alto y bajo grado respectivamente. La correlación entre CDA y celularidad fue débil (R = - 0.13, p = 0.37).</p><p><br />Conclusión: Existe correlación débil inversamente proporcional entre el CDA y la celularidad con distinción de gliomas de bajo y alto grado con valores de CDA mínimos.<br /><br /> <br />Abstract<br />Introduction: Gliomas are highly cellular malignant tumors of the central nervous system. Itspreoperative histological grade is useful in surgical management,so magnetic resonance imaging with advanced sequences tries to provide more tumor information.</p><p><br />Objective:Correlateapparent diffusion coefficient (ADC) and cellularity of gliomas of patients between January 2015 to December 2017.<br />Methodology:Data of age, sex, type, histologic grade and anatomic site were retrospectively obtained from clinical archives.The preoperative magnetic resonance ADC was calculated in a 5 mm2 region of interest and the microscope slides were used for the cellularity digitally count in 5 mm2. Descriptive statistical analysis and correlation coefficient between ADC and cellularity were used. Values of p <0.05 were used for statistical significance.</p><p><br />Results: 46 cases were included, 56.5% were men. The 41-64 years ranges were the most affected. Glioblastoma was the most frequent histological type (47.8%), as well as high grade gliomas (73.9%). 95.7% were supratentorial. The average cellularity was 3970 ± 2900 vs 2436 ± 948 nuclei/ 5mm2 (p = 0.13), with average minimum ADC values of 0.813 x 10-3 ± 0.229 mm2/s vs 1052 x 10-3 ± 0.196 mm2/s (p = 0.002), for high- and low-grade gliomas, respectively. The correlation between ADC and cellularity was weak (R = - 0.13, p = 0.37).</p><p><br />Conclusions:There is a weak inversely proportional correlation between ADC and cellularity. With distinction of low- and high-grade gliomas with minimum ADC values.<br /><br /></p>