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Questions tagged [propositional-logic]

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364 views

Iota combinator and implicational propositional calculus

There is are two esoteric languages with minimally functionally complete operators, iota and jot, that are closely related to SK combinators. I'm attempting to understand the relationship between ...
232 views

Which formula corresponds to this K-Map?

I have a K-Map and I need to figure out which expression isn't equivalent to the provided K-Map. $f(w,x,y,z) = \sum(3,7,9,11,13,15) + \Phi(4,5,6)$ We know that both options (a) and (b) are ...
232 views

Relations between statements involving universal quantifier, conditional and biconditional

If we consider two predicates: $b(x)$: x is a boy $c(x)$: x is clever Then, there are four statements involving $∀, b(x), c(x), →$ and $↔$ . These are below along with my interpretation of their ...
48 views

Transform $A\land B \Leftrightarrow B\lor A$ into conjunctive normal form [closed]

How do I transform the following formula into conjunctive normal form? $$A \land B \Leftrightarrow B \lor A$$
187 views

How to find a minimum set of axioms within a set of propositions?

I have a set of propositions, for example $\{a_1,a_2,\dots,a_n\}$. Some propositions depend on others (for example, $a_1,a_2\Rightarrow a_3$, means if $a_1,a_2$ are true, then $a_3$ is true). I want ...
2k views

Find hamilton cycle in a directed graph reduced to sat problem

I need to find a Hamiltonian cycle in a directed graph using propositional logic, and to solve it by sat solver. So after I couldn't find a working solution, I found a paper that describes how to ...
866 views

How to decide if a propositional formula is a well formed?

So, I have the following propositional formula: (((P → Q) ∨ S) ↔ T) How do I decide if it's well formed?
78 views

Non-deterministic algorithms and Tautologies

I am studying the lecture The Complexity of Propositional Proofs. ​Here there is a definition together with a discussion (page 3). I don't understand that discussion. Let $F$ denote the set of ...
320 views

Size of Propositional Formula

I am study this lecture The Complexity of Propositional Proofs. Here there is a term size of propositional formula (page 2), Every tautology $\tau$ on $n$ variables has an $F$-proof in which thera ...
4k views

Boolean algebraic expression vs Propositional logic expression

There is a lot of similarity between Propositional logic and Boolean algebraic expressions. Similar aspects : 1) Both has variables of two states. 2) Operations of Boolean algebra and ...
103 views

Complexity of a SAT related problem

Given a set of (propositional) formulae $\Phi$, two formulae $\phi$ and $\xi$, determine whether there exists $\Psi\subseteq \Phi$ such that $\Psi\models \phi$ and $\Psi\not\models \xi$. Question: ...
9k views

Operator precedence in propositional logic

there is some kind of priorities for the elements in propositional logic ? for example : p ∧¬q → r , given this ,we there may be two options (p ∧¬q) → r OR p ∧ (¬q → r) , which one is the correct ?...
89 views

Learning a small disjunction

I have a boolean function $f: \{0,1\}^n \to \{0,1\}$ that I know takes the form $$f(x_1,\dots,x_n) = x_{i_1} \lor x_{i_2} \lor \dots \lor x_{i_k},$$ but I don't know the values of $i_1,\dots,i_k$. ...
133 views

Is there a known way to convert any $QBF_2$-formula into an equisatisfiable $QBF_2$-formula in CNF in polynomial time?

It is easy to turn any boolean formula and any quantified boolean formula into an equisatisfiable formula in CNF using Tseitin transformation:  Q_1 z_1 Q_2 z_2 \ldots Q_n z_n \Phi \Rightarrow Q_1 ...
61 views

Efficiently decidable logics

So propositional logic (PL) is efficiently (in P) decidable because I can convert formulas to an equisatisifiable CNF-formula, negate and convert (efficiently, by De Morgans laws) to DNF. I can then ...
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What is the difference between the situation calculus and the propositional logic of context?

I have been reading a lot of papers by John McCarthy lately. As early as 1963, he developed the situation calculus, but then starting in 1987, he developed what came to be known as the propositional ...
39 views

106 views

Using the rules of inferences

I know the rules of inferences and logical equivalence but I cannot seem to validate this argument. I rewrote the first premise as $\neg p\vee q$ other from that I am stuck. Any help will be ...
240 views

Propositional logic — syntactical completeness

Lets consider propositional logic. We say a proof system for propositional logic is syntactically (negation) complete if for every $\alpha$, either $\alpha$ or $\neg \alpha$ are provable within the ...
232 views

Real life description for (~A->A)->A

It can be shown that the logical preposition [ :- (~A->A)->A ] is a theorem (always true). I want to know if anybody knows a real life description for the preposition above? I mean an expression in ...
69 views

Satisfiabilty 2-sat

Im trying to work out whether the following clause is satisfiable: {x, y},{x,¬y},{¬x, y},{¬x,¬y},{x, z},{x,¬z},{y, z},{y,¬z} My basic understanding is to work ...
89 views

Propositional logic of arguments and undercuts [closed]

The setting An argument from a set of formulas $\Delta$ is a pair $\langle \Phi, \alpha \rangle$ such that $\Phi \subseteq \Delta$ $\Phi \nvdash \bot$ $\Phi \vdash \alpha$ (this is what I am ...