This volume is a homage to the computer scientist and philosopherTarcísio Haroldo Cavalcante Pequeno. Tarcísio dedicated his researchto subjects ranging from logic to philosophy through artificialintelligence, theoretical computer science and language. His maincontributions were in nonmonotonic and paraconsistent logics,especially the study of negation; algebraic approaches to the semanticsof programming languages, applications of intuitions from gamesemantics to automatic theorem proving; tableaux methods forparaconsistent logics and the role of rule following and ruleconsciousness in cognition, motivated by his interest in philosophyand the problem of demarcation of rationality.The contributions to this volume reflect the broad range of interests characteristic ofTarcísio's scientific interests. Topics include relations betweenlogic and category theory, specifications of model checkers,philosophy of paraconsistent logics, epistemic logic, abstractargumentation semantics, natural language processing, foundations ofmathematics, philosophical aspects of natural language processing,philosophy of logic and language, metaphysics, philosophy of science.During the last forty years, Tarcísio oriented, inspired andcollaborated with many researchers and established the field of logicas an active research area in Northeast Brazil. This book expressesthe admiration of his colleagues and the recognition of his influenceon their academic lives.
