Newbetuts

A is a proposition formula that contains only iff. A is a tautology iff each atomic proposition in A appears an even number of times.

"false implies true" is a true statement [duplicate]

How to prove that $[(p \to q) \land (q \to r)] \to (p \to r)$ is a tautology without using the truth table?

Confusion over the definition of "model"

Critique my proof of: Suppose $A$, $B$, and $C$ are sets, and $A\setminus B \subseteq C$. Then $A\setminus C \subseteq B$.

Derive $P \to \neg \neg P$ in a structure with not and implies

What's the difference between $\equiv$ and $\leftrightarrow$ in a formal proof?

Critique my proof of: P → (Q → R). Then ¬R → (P → ¬Q)

What is Validity and Satisfiability in a propositional statement?

Proving that if $\Gamma \cup \{\gamma\}$ is inconsistent, then $\Gamma\vdash \neg\gamma$.

Induction proof for the lengths of well-formed formulas (wffs)

Truth tables in propositional calculus: semantic or syntactic in nature?

Solving SAT by converting to disjunctive normal form

Problem in understanding p implies q

New posts in propositional-calculus

If null set is an element of a set then will it belongs to set or subset? [closed]

Translating "therefore" in propositional logic and using contradictions to prove an argument.

Find DNF and CNF of an expression

Show that $\Gamma \cup \{\neg \phi\}$ is satisfiable if and only if $\Gamma\not \models \phi$

Why $¬¬\bot \not\in PROP$?

Does double negation distribute over implication intuitionistically?

A is a proposition formula that contains only iff. A is a tautology iff each atomic proposition in A appears an even number of times.

"false implies true" is a true statement [duplicate]

How to prove that $[(p \to q) \land (q \to r)] \to (p \to r)$ is a tautology without using the truth table?

Confusion over the definition of "model"

Critique my proof of: Suppose $A$, $B$, and $C$ are sets, and $A\setminus B \subseteq C$. Then $A\setminus C \subseteq B$.

Derive $P \to \neg \neg P$ in a structure with not and implies

What's the difference between $\equiv$ and $\leftrightarrow$ in a formal proof?

Critique my proof of: P → (Q → R). Then ¬R → (P → ¬Q)

What is Validity and Satisfiability in a propositional statement?

Proving that if $\Gamma \cup \{\gamma\}$ is inconsistent, then $\Gamma\vdash \neg\gamma$.

Induction proof for the lengths of well-formed formulas (wffs)

Truth tables in propositional calculus: semantic or syntactic in nature?

Solving SAT by converting to disjunctive normal form

Problem in understanding p implies q