Prove $(\forall x\ Q(x))\to P ⊢ \exists x (Q(x)\to P)$ using Natural Deduction
48368
Prove using Natural Deduction in predicate logic $(\forall x\ P(x))\to Q ⊢ \exists x (P(x)\to Q)$
52585
How to prove that $[(p \to q) \land (q \to r)] \to (p \to r)$ is a tautology without using the truth table?
1027
Why is this true? $(\exists x)(P(x) \Rightarrow (\forall y) P(y))$
157924
$\forall x\in\mathbb{N}[(\exists y\in\mathbb{N}(2\leq y\land y<x\land y\ |\ x))\to(\exists z\in\mathbb{N}(2\leq z\land z\leq\sqrt x\land z\ |\ x))]$
88281
Mixing and Distributing Qualifiers ($\forall x$, $\exists x$)
49994
Deduction of $\forall y \exists x (x=y)$
126870
Show that axiom of replacement implies from the Axiom of Specification [Proof Verification]
48592
Prove that $f'$ exists for all $x$ in $R$ if $f(x+y)=f(x)f(y)$ and $f'(0)$ exists
76347
Shorter proof for some equvalences
6535
Proof of for-all / there-exists "negation"?
93707
Formal proof for $q \land \neg q \vdash r \land \neg r$
104771
Dedekind's cut and axioms
37134
How can I solve this logic question using propositional logic (Natural deduction)?
113605
In Fitch, how does one prove "(P → Q)" from the premise "(¬P ∨ Q)"?
6119
If both $P$ and $Q$ are true , how can I tell that $P$ implies $Q$?
21035
Clarifying on how if p,q is logically equivalent to p only if q
46939
Natural deduction, Proof $\vdash$ $P\Rightarrow(Q\Rightarrow P)$