How to prove (P ∧ ¬Q) ↔ ¬(P → Q)
37369
How do I check if two logical expressions are equivalent?
70117
Show that $(p \to q) \lor (q \to p)$ is a tautology
140194
Using natural deduction to prove that $p \implies q \vdash \lnot p \lor q$
50178
\qed for theorems without proofs
4303
Enumerating inside a proposition and inside a proof
46939
Natural deduction, Proof $\vdash$ $P\Rightarrow(Q\Rightarrow P)$
22856
Ways to go from A to B(proof)
37196
"If P, then Q; If P, then R; Therefore: If Q, then R." Fallacy and Transitivity
32027
Given (p ∧ q), use the Fitch system to prove (q ∨ r)
578
In classical logic, why is $(p\Rightarrow q)$ True if both $p$ and $q$ are False?
144396
fitch style proof problem regarding rule of inferences
123458
Prove $( \lnot C \implies \lnot B) \implies (B \implies C)$ without the Deduction Theorem
143248
What approach should I take to establish this logical proof?
34768
Proving $(p \oplus q) \oplus r=p \oplus (q \oplus r)$
32009
Prove $\;\big((p\rightarrow q) \lor (p \rightarrow r)\big) \rightarrow (q\lor r)\equiv p \lor q \lor r$ without use of a truth table.
49994
Deduction of $\forall y \exists x (x=y)$
56351
Prove that these statements $(A \lor \neg B)$ and $\neg A \to \neg B$ are logically equivalent