Proving some property of a Formal Logic Language
140682
Proving a property of a Logic Formal Language
72185
The negation of a limit condition, Spivak style.
87928
Proof of logical equivalence of biconditional and other proposition
15354
Formal proof of $\exists x \forall y P(x,y) \implies \forall y \exists x P(x,y)$
138897
help with some Hilbert style proofs in a propositional logic axiom system.
135267
Predicate Logic and Inference
103463
Mantel's Theorem proof verification
140194
Using natural deduction to prove that $p \implies q \vdash \lnot p \lor q$
49385
Proving $\forall x (A\to B) \to(A \to \forall x B):x\notin \mbox{free}(A)$ in a Hilbert system where it is not an axiom
93410
How to prove ~ (~P & ~Q) : P ∨ Q by natural deduction
61635
Proving AM-GM with induction
51369
Natural deduction proof of $p \lor (p\implies q)$ with propositional calculus
93707
Formal proof for $q \land \neg q \vdash r \land \neg r$
141260
Prove using the formal definition of a limit that
153975
Proving mathematical induction with arbitrary base using (weak) induction
59964
Why an inconsistent formal system can prove everything?
108367
proving tautologically equivalent