Proof-theoretic Semantics for Intuitionistic Multiplicative Linear Logic

This work is the first exploration of proof-theoretic semantics for a substructural logic. It focuses on the base-extension semantics (B-eS) for intuitionistic multiplicative linear logic (IMLL). The starting point is a review of Sandqvist’s B-eS for intuitionistic propositional logic (IPL), for which we propose an alternative treatment of conjunction that takes the form of the generalized elimination rule for the connective. The resulting semantics is shown to be sound and complete. This motivates our main contribution, a B-eS for IMLL , in which the definitions of the logical constants all take the form of their elimination rule and for which soundness and completeness are established

Modal paraconsistent logic

Dissertação de mestrado integrado em Engenharia FísicaSuperconducting quantum circuits are a promising model for quantum computation, al though their physical implementation faces some adversities due to the hardly unavoidable decoherence of superconducting quantum bits. This problem may be approached from a formal perspective, using logical reasoning to perform software correctness of programs executed in the non-ideal available hardware. This is the motivation for the work devel oped in this dissertation, which is ultimately an attempt to use the formalism of transition systems to design logical tools for the engineering of quantum software. A transition system to capture the possibly unexpected behaviors of quantum circuits needs to consider the phenomena of decoherence as a possible error factor. In this way, we propose a new family of transition systems, the Paraconsistent Labelled Transition Systems (PLTS), to describe processes that may behave differently from what is expected when facing specific contexts. System states are connected through transitions which simultaneously characterize the possibility and impossibility of that being the system’s evolution. This kind of formalism may be used to represent processes whose evolution is impossible to be sharply described and, thus, should be able to cope with inconsistencies, as well as with vagueness or missing information. Besides giving the formal definition of PLTS, we establish how they are related under the notions of morphism, simulation, bisimulation and trace equivalence. It is a common practice to combine transition systems through universal constructions, in a suitable category, which forms a basis for a process description language. In this dis sertation, we define a category of PLTS and propose a number of constructions to combine them, providing a basis for such a language. Transition systems are usually associated with modal logics which provide a formal set ting to express and prove their properties. We also propose a modal logic, more specifically, a modal intuitionistic paraconsistent logic (MIPL), to talk about PLTS and express their properties, studying how the equivalence relations defined for PLTS extend to relations on MIPL models and how the satisfaction of formulas is preserved along related models. Finally, we illustrate how superconducting quantum circuits may be represented by a PLTS and propose the use of PLTS equivalence relations, namely that of trace equivalence, to compare circuit effectiveness.Os circuitos quânticos que operam qubits supercondutores são um modelo promissor para a arquitetura de computadores quânticos. No entanto, a sua implementação física pode tornar-se ineficaz, devido a fenómenos de decoerência a que os qubits em questão estão altamente sujeitos. Uma possível abordagem a este problema consiste em empregar a lógica e as suas ferramentas para a correção de programas a executar nestes dispositivos. A proposta desta dissertação é que se utilize o formalismo dos sistemas de transição para modelar e descrever o comportamento dos circuitos quânticos, que, por vezes, pode ser imprevisível. Para tal, considera-se a decoerência de qubits como um possível fator de erro nas computações. Assim surge uma nova família de sistemas de transição, os Paraconsistent Labelled Transition systems (PLTS), como um modelo para descrever processos que, em determinados contextos, se comportam de forma diferente do que é esperado. Os estados de um PLTS estão conectados por transições que caracterizam, simultaneamente, a possibilidade e a impossibilidade de o sistema evoluir transitando de um estado para o outro. Este é um modelo em que a informação acerca das transições pode ser incompleta ou mesmo contraditória. Além da definição formal dos PLTS, são também sugeridas, como relações entre PLTS, as noções de morfismo, simulação, bissimulação e equivalência por traços. Muitas vezes, os sistemas de transição são combinados através de construções universais numa categoria adequada, de forma a definir uma álgebra de processos. Também neste trabalho é definida uma categoria de PLTS e são propostas algumas construções, típicas nas álgebras de processos, para os combinar. Os sistemas de transição são geralmente associados a lógicas modais, que permitem expressar e provar as suas propriedades. A definição dos PLTS conduziu à definição de uma lógica modal, MIPL, que permitiu determinar de que forma as relações de equivalência definidas para PLTS, e estendidas para modelos da logica MIPL, se refletem na preservação da satisfação de fórmulas sobre os modelos relacionados. Por fim, propõe-se utilizar PLTS para a representação de circuitos quânticos e comparar a eficácia dos circuitos através da relação de equivalência por traços

Constructive Fuzzy Logics

We generalise Kripke’s semantics for Intuitionistic logic to Hajek’s BL and consider the constructive subsystems of GBLewf and Intuitionistic Affine logic or ALi. The genesis of our semantics is the Poset Product construction for GBL-algebras elucidated in a series of papers by Peter Jipsen, Simone Bova, and Franco Montagna. We present natural deduction systems for all of these systems and corresponding deduction theorems for these same. We present the algebraic semantics for each of the logics under consideration, demonstrate their soundness and completeness with respect to these algebraic semantics. We also show how the classical Kripke semantics for Intuitionistic logic can be recast in terms of Poset Products. We then proceed to the main results, showing how a very natural generalisation of the Kripke semantics holds for each of GBLewf , ALi and Hajek’s BL based on the embedding results of Jipsen and Montagna and the decidability results of Bova and Montagna. We demonstrate soundness and completeness of the logics under our semantics in each case, with the exception of ALi, whose robust completeness with respect to the intended models (relational models with frames valued in involutive pocrims) we leave as an open problem for the ambitious reader

19th Brazilian Logic Conference: Book of Abstracts

This is the book of abstracts of the 19th Brazilian Logic Conferences. The Brazilian Logic Conferences (EBL) is one of the most traditional logic conferences in South America. Organized by the Brazilian Logic Society (SBL), its main goal is to promote the dissemination of research in logic in a broad sense. It has been occurring since 1979, congregating logicians of different fields — mostly philosophy, mathematics and computer science — and with different backgrounds — from undergraduate students to senior researchers. The meeting is an important moment for the Brazilian and South American logical community to join together and discuss recent developments of the field. The areas of logic covered in the conference spread over foundations and philosophy of science, analytic philosophy, philosophy and history of logic, mathematics, computer science, informatics, linguistics and artificial intelligence. Previous editions of the EBL have been a great success, attracting researchers from all over Latin America and elsewhere. The 19th edition of EBL takes place from May 6-10, 2019, in the beautiful city of João Pessoa, at the northeast coast of Brazil. It is conjointly organized by Federal University of Paraíba (UFPB), whose main campus is located in João Pessoa, Federal University of Campina Grande (UFCG), whose main campus is located in the nearby city of Campina Grande (the second-largest city in Paraíba state) and SBL. It is sponsored by UFPB, UFCG, the Brazilian Council for Scientific and Technological Development (CNPq) and the State Ministry of Education, Science and Technology of Paraíba. It takes place at Hotel Luxxor Nord Tambaú, privileged located right in front Tambaú beach, one of João Pessoa’s most famous beaches

Categories and logical syntax

The notions of category and type are here studied through the lens of logical syntax: Aristotle's as well as Kant's categories through the traditional form of proposition `S is P', and modern doctrines of type through the Fregean form of proposition `F(a)', function applied to argument. Topics covered include the conception of categories as highest genera; the parts of speech and their relation to categories; the attempt to derive categories from more fundamental notions; the notion of a range of significance; the notion of a type assignment; sortal concepts and the notions of identity and generality; and the distinction between formal and material categories.UBL - phd migration 201

Coinductive Equivalences and Metrics for Higher-order Languages with Algebraic Effects

This dissertation investigates notions of program equivalence and metric for higher-order sequential languages with algebraic effects. Computational effects are those aspects of computation that involve forms of interaction with the environment. Due to such an interactive behaviour, reasoning about effectful programs is well-known to be hard. This is especially true for higher-order effectful languages, where programs can be passed as input to, and returned as output by other programs, as well as perform side-effects. Additionally, when dealing with effectful languages, program equivalence is oftentimes too coarse, not allowing, for instance, to quantify the observable differences between programs. A natural way to overcome this problem is to re ne the notion of a program equivalence into the one of a program distance or program metric, this way allowing for a finer, quantitative analysis of program behaviour. A proper account of program distance, however, requires a more sophisticated theory than program equivalence, both conceptually and mathematically. This often makes the study of program distance way more di cult than the corresponding study of program equivalence