Proving a logical implication using modus ponens and metatheorems
32244
Propositional Logic - Deduction
87928
Proof of logical equivalence of biconditional and other proposition
53056
natural deduction: introduction of universal quantifier and elimination of existential quantifier explained
98386
First-order logic and second-order logic confusion
93410
How to prove ~ (~P & ~Q) : P ∨ Q by natural deduction
62936
Proving equivalencies of two versions of the Axiom of Choice
113065
Proving equivalences of statements equivalent to AC
91861
Propositional Logic: p → q, ¬p → r, ¬q → ¬r ⊢ q
147375
Prove :(P → Q) ∨ (Q → P) using natural deduction
43655
Verify is tautology by using logical equivalence
140194
Using natural deduction to prove that $p \implies q \vdash \lnot p \lor q$
109325
Euclid Lemma proof reasoning
141952
Is there a decision procedure for intuitionistic propositional logic?
142840
Open axioms of equality
56351
Prove that these statements $(A \lor \neg B)$ and $\neg A \to \neg B$ are logically equivalent
16187
proof of functional completeness of logical operators
20004
Meta Theory when studying Set Theory