S→∃x.Q(x) ⊢ ∃x.(S→Q(x)): How to prove the validity of this sequent in predicate logic?
87257
How to prove this sequent using natural deduction?
32027
Given (p ∧ q), use the Fitch system to prove (q ∨ r)
142762
how to prove that (P⊃Q)≡(¬Q⊃¬P) ( P ⊃ Q ) ≡ ( ¬ Q ⊃ ¬ P ) is disallowed in intuitionistic logic?
52585
How to prove that $[(p \to q) \land (q \to r)] \to (p \to r)$ is a tautology without using the truth table?
103112
Does the existential quantifier distribute over an implication?
151356
Need Hints Prove "$((\neg \alpha \to \alpha) \to \alpha) $" Using Axiom 1,2,3 and MP and deduction theorem
29679
Prove: $|x-y|\leq |x|+|y|$
70166
Why is the universal quantifier $\forall x \in A : P(x)$ defined as $\forall x (x \in A \implies P(x))$ using an implication?
93707
Formal proof for $q \land \neg q \vdash r \land \neg r$
48606
Help with a Predicate Logic homework proof
126870
Show that axiom of replacement implies from the Axiom of Specification [Proof Verification]
86248
Is $\exists x(x=a)$ a valid formula in first order logic with equality?
53101
Is it true that the relation |A| < |B| is a sufficient condition for claiming that $f$ is a bijection?
6119
If both $P$ and $Q$ are true , how can I tell that $P$ implies $Q$?
81618
Prove $||a|-|b| | \leq |a-b|$
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?
49994
Deduction of $\forall y \exists x (x=y)$