Truth table for $p \implies q$
42590
Understanding implication in logic truth tables (excerpt from textbook)
15354
Formal proof of $\exists x \forall y P(x,y) \implies \forall y \exists x P(x,y)$
142762
how to prove that (P⊃Q)≡(¬Q⊃¬P) ( P ⊃ Q ) ≡ ( ¬ Q ⊃ ¬ P ) is disallowed in intuitionistic logic?
31299
Using the Fitch system, how do I prove $((p \implies q) \implies p)\implies p$?
35236
Proof $p \vdash q \Rightarrow p$
79407
How to solve ~(P → Q) : P & ~Q by natural deduction?
48368
Prove using Natural Deduction in predicate logic $(\forall x\ P(x))\to Q ⊢ \exists x (P(x)\to Q)$
84251
Show that $\Gamma \cup \{\neg \phi\}$ is satisfiable if and only if $\Gamma\not \models \phi$
77759
How do i prove that $(p \vee q) \wedge (\neg p \vee r) \rightarrow (q \vee r)$ is a tautology without using the truth table?
62936
Proving equivalencies of two versions of the Axiom of Choice
106797
Truth Tables for Digital Circuits
148585
Show that, for any $\epsilon>0$, there exist two rationals such that $q < x < q'$ and $|q-q'|<\epsilon$
45481
Prove or disprove validity: $(\forall x \exists y (P(x) \supset Q(y))) \supset(\exists y \forall x (P (x) \supset Q(y)))$
134384
What does $\rightarrow$ mean in $p \rightarrow q$
148790
Basic question about proofs with the goal $\exists x P(x)$
139278
If $\Gamma$ is satisfiable then $\Gamma$ is consistent
115726
For $p,q$ prime and $p \neq q$ show that $C_p \times C_q \cong C_{pq}$