Trends in Logic is the conference series of the journal Studia Logica (see __www.studialogica.org__ and __link.springer.com__).

\;The 20th Trends in Logic international conference\, **Logic and Reasoning: Formal and Informal**\, will be held at the Taras Shevchenko National University of Kyiv\, Kyiv\, Ukraine\, May 13-15\, 2020. It is organized by the Department of Logic at the Faculty of Philosophy of the Taras Shevchenko National University of Kyiv\, in co-operation with Studia Logica.

\;Reasoning is at the very heart of logic\, constituting its subject matter. In the last few decades\, there has been considerable progress both in the purely logical analysis of reasoning and in applied logical investigations of various concrete subject domains\, such as philosophical and scientific discourse\, logic programming and everyday communication. Reasoning has been studied from proof-theoretical as well as semantic standpoints. Along with further elaboration of standard techniques (axiomatic systems\, sequent calculi and natural deduction) a range of other approaches (such as display calculi\, tableaux methods\, hypersequent systems\, etc.) and semantic modelling of logical systems are being developed. Moreover\, there is a powerful tradition of analyzing and evaluating reasoning patterns by means of informal logic and argumentation theory. Recent advances in these fields\, in particular\, constructing theoretical models of argumentation and dialectical systems\, have proved promising. The aim of the conference is to bring together scholars working in various areas of proof-theoretic\, semantic\, argumentative and informal logic analysis. The topics of interest may include\, but are not limited to:

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- modern approaches to proof theory\; \n
- structural proof theory and structural reasoning\; \n
- proof-theoretic methods in non-classical logics\; \n
- proof-theoretic semantics\; \n
- Kripke models and algebraic methods in semantics\; \n
- semantic analysis of non-classical logics\; \n
- semantic modelling of knowledge representation and reasoning\; \n
- provability logic\; \n
- description logic\, defeasible reasoning and non-monotonic logic\; \n
- inductive reasoning and probabilistic logic\; \n
- automated reasoning\; \n
- formal models of argumentation\; \n
- abstract argumentation systems\; \n
- argumentation schemes and patterns\; \n
- practical reasoning and argumentation\, argumentation in interpersonal communication\; \n
- argumentation in special contexts: finance\, medicine\, law\, policy making\, academy\, (social) media\, etc.\; \n
- dialogue logic\, empirical logic\, informal logic\; \n
- informal fallacies and cognitive biases in relation to reasoning. \n