scholarly journals Consistent posets

2021 ◽  
Author(s):  
Ivan Chajda ◽  
Helmut Länger

AbstractWe introduce so-called consistent posets which are bounded posets with an antitone involution $$'$$ ′ where the lower cones of $$x,x'$$ x , x ′ and of $$y,y'$$ y , y ′ coincide provided that x, y are different from 0, 1 and, moreover, if x, y are different from 0, then their lower cone is different from 0, too. We show that these posets can be represented by means of commutative meet-directoids with an antitone involution satisfying certain identities and implications. In the case of a finite distributive or strongly modular consistent poset, this poset can be converted into a residuated structure and hence it can serve as an algebraic semantics of a certain non-classical logic with unsharp conjunction and implication. Finally we show that the Dedekind–MacNeille completion of a consistent poset is a consistent lattice, i.e., a bounded lattice with an antitone involution satisfying the above-mentioned properties.

2016 ◽  
Vol 66 (4) ◽  
Author(s):  
Ivan Chajda ◽  
Sándor Radeleczki

AbstractSeveral characterizations of orthomodular lattices based on properties of an antitone involution or on sectional antitone involutions are given. Another approach is based on properties of the implication operation which can be derived in every orthomodular lattice but can be also added to basic operations of a bounded lattice. Finally, we introduce the so-called weakly orthomodular lattice as a generalization of orthomodular lattices.


2021 ◽  
Vol 56 ◽  
pp. 75-99
Author(s):  
Satoru Niki ◽  
Hitoshi Omori

We investigate an expansion of positive intuitionistic logic obtained by adding a constant Ω introduced by Lloyd Humberstone. Our main results include a sound and strongly complete axiomatization, some comparisons to other expansions of intuitionistic logic obtained by adding actuality and empirical negation, and an algebraic semantics. We also brie y discuss its connection to classical logic.


2010 ◽  
Vol 30 (11) ◽  
pp. 2932-2936
Author(s):  
Ling-zhong ZHAO ◽  
Xue-song WANG ◽  
Jun-yan QIAN ◽  
Guo-yong CAI

Author(s):  
Alexander R. Pruss

It seems that counterfactuals and many other statements are subject to semantic underdetermination. Classical logic pushes one to an epistemicist account of this underdetermination, but epistemicism seems implausible. However epistemicism can be made plausible when conjoined with a divine institution account of meaning. This gives us some reason to accept that divine institution account, and hence some reason to think that God exists. This chapter evaluates the arguments for epistemicism and divine institution, including objections, and incorporates Plantinga’s consideration of counterfactuals when it comes to theism. In particular, an analogy is drawn with divine command and natural law theories in ethics.


Author(s):  
Lucas Champollion

Why can I tell you that I ran for five minutes but not that I *ran all the way to the store for five minutes? Why can you say that there are five pounds of books in this package if it contains several books, but not *five pounds of book if it contains only one? What keeps you from using *sixty degrees of water to tell me the temperature of the water in your pool when you can use sixty inches of water to tell me its height? And what goes wrong when I complain that *all the ants in my kitchen are numerous? The constraints on these constructions involve concepts that are generally studied separately: aspect, plural and mass reference, measurement, and distributivity. This work provides a unified perspective on these domains, connects them formally within the framework of algebraic semantics and mereology, and uses this connection to transfer insights across unrelated bodies of literature and formulate a single constraint that explains each of the judgments above. This provides a starting point from which various linguistic applications of mereology are developed and explored. The main foundational issues, relevant data, and choice points are introduced in an accessible format.


2021 ◽  
pp. 1-15
Author(s):  
Geoff Sutcliffe

The CADE ATP System Competition (CASC) is the annual evaluation of fully automatic, classical logic Automated Theorem Proving (ATP) systems. CASC-J10 was the twenty-fifth competition in the CASC series. Twenty-four ATP systems and system variants competed in the various competition divisions. This paper presents an outline of the competition design, and a commentated summary of the results.


2021 ◽  
Vol 82 (2) ◽  
Author(s):  
Sándor Radeleczki

AbstractG. Czédli proved that the blocks of any compatible tolerance T of a lattice L can be ordered in such a way that they form a lattice L/T called the factor lattice of L modulo T. Here we show that the Dedekind–MacNeille completion of the lattice L/T is isomorphic to the concept lattice of the context (L, L, R), where R stands for the reflexive weak ordered relation $$ \mathord {\le } \circ T$$ ≤ ∘ T . Weak ordered relations constitute the generalization of the ordered relations introduced by S. Valentini. Reflexive weak ordered relations can be characterized as compatible reflexive relations $$R\subseteq L^{2}$$ R ⊆ L 2 satisfying $$R=\ \mathord {\le } \circ R\circ \mathord {\le } $$ R = ≤ ∘ R ∘ ≤ .


2021 ◽  
Author(s):  
Ivan Chajda ◽  
Helmut Länger

AbstractTogether with J. Paseka we introduced so-called sectionally pseudocomplemented lattices and posets and illuminated their role in algebraic constructions. We believe that—similar to relatively pseudocomplemented lattices—these structures can serve as an algebraic semantics of certain intuitionistic logics. The aim of the present paper is to define congruences and filters in these structures, derive mutual relationships between them and describe basic properties of congruences in strongly sectionally pseudocomplemented posets. For the description of filters in both sectionally pseudocomplemented lattices and posets, we use the tools introduced by A. Ursini, i.e., ideal terms and the closedness with respect to them. It seems to be of some interest that a similar machinery can be applied also for strongly sectionally pseudocomplemented posets in spite of the fact that the corresponding ideal terms are not everywhere defined.


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