Formal proof for this predicate logic problem.
1027
Why is this true? $(\exists x)(P(x) \Rightarrow (\forall y) P(y))$
87257
How to prove this sequent using natural deduction?
96748
Formal deductions on Hilbert system
46423
Distributivity of quantifiers over logical connectives
20252
The Axiom of Choice and the Cartesian Product.
134319
When induction proofs need a choice function
46550
Proving an 'obvious' Ramsey upperbound
140682
Proving a property of a Logic Formal Language
29110
Propositional Intuitionistic Logic Question
53056
natural deduction: introduction of universal quantifier and elimination of existential quantifier explained
94617
Showing Consistency and Completeness implies a unique truth assignment
150451
Logic soundness and completeness
9077
Proof that no term (of a language of predicate logic) is a (non-empty) initial segment of another
151561
Proving 'Law of Excluded Middle' in Fitch system
32181
A logic puzzle involving a balance.
158295
First Order Logic clauses decidability
87928
Proof of logical equivalence of biconditional and other proposition