From the very beginning, logicians have counted practical (or action-oriented) reasoning as well as theoretical (or belief-oriented) reasoning as part of their subject. However, despite a tradition that continues to the present, logicians have not produced formalisms that could be considered of any use in designing an agent that needs to act intelligently, or in helping an intelligent agent to ...

Description logics are a family of knowledge representation formalisms that are descended from semantic networks and frames via the system Kl-one. During the last decade, it has been shown that the important reasoning problems (like subsumption and satissability) in a great variety of description logics can be decided using tableau-like algorithms. This is not very surprising since description ...

in this paper by use of mathematical modeling of an observer [14,15] the notion of relative information functional for relative dynamical systemson compact metric spaces is presented. we extract the information function ofan ergodic dynamical system (x,t) from the relative information of t fromthe view point of observer χx, where x denotes the base space of the system.we also generalize the inv...

How can we know if a proof is correct? People often imagine that it suffices for a mathematician to make the effort to read it carefully, line by line, after having taken note of the definitions and known results that might be of use. If certain questions are unresolved, as to be sure some are, we would known precisely which ones, and the work of the researcher would consist uniquely of resolvi...

One of the main reasons why classical logic is not always the most adequate tool for describing human knowledge is that in many real-life situations, we have some arguments in favor of a certain statement A and some arguments in favor of its negation ¬A. As a result, we want to consider both A and ¬A to be (to some extent) true. Classical logic does not allow us to do that, while in fuzzy logic...

In the beginning of the 20th century, many prominent logicians and mathematicians, such as Frege, Russell, Hilbert, and many others, felt that mathematics needed a very rigorous foundation in logic. The standard approach in the early part of the 20th century was to use a syntactic or proof-theoretic definition of logical consequence. This says that “for one sentence to be a logical consequence ...

Abstract Are children better off than their parents? This highly debated question in politics and economics is investigated by analysing the trends absolute relative intergenerational labour income mobility for Germany US. High quality panel data used this purpose; SOEP PSID In Germany, 67% of sons born between 1955 1975 earned a significantly higher real long-run fathers. Those with fathers fr...

We present nine questions related to the concept of negation and, in passing, we refer connections with essays this special issue. The were submitted one most eminent logicians who contributed theory negation, Prof. (Jon) Michael Dunn, but, unfortunately, Dunn was no longer able answer them. passed away on 5 April 2021, and issue Logical Investigations is dedicated his memory. concern (i) negat...

Abstract The use of the symbol $\mathbin {\boldsymbol {\vee }}$ for disjunction in formal logic is ubiquitous. Where did it come from? paper details evolution its historical and logical context. Some sources say that as connecting propositions or formulas was introduced by Peano; others suggest originated an abbreviation Latin word “or,” vel . We show origin can be traced to Whitehead Russell’s...

In recent years model-based reasoning has achieved a certain prominence among logicians and cognitive scientists. Its repute is deserved, notwithstanding that it has some vigorous rivals. Although both model-based and non-model-based systems aim at elucidations of good reasoning, there are certain issues that challenge them equally across the lines of their respective theoretical and methodolog...