How to prove ⊢B→(A→B) (no premise) using natural deduction?
46939
Natural deduction, Proof $\vdash$ $P\Rightarrow(Q\Rightarrow P)$
109858
How could a statement be true without proof?
100844
How should I understand "$A$ unless $B$"?
47135
Prove if a = b, then f(a) = f(b) for any function f (with natural deduction)
152817
Proving $\sup B=\inf A$
140167
Proving $A+A'B=A+B$ without truth tables
48368
Prove using Natural Deduction in predicate logic $(\forall x\ P(x))\to Q ⊢ \exists x (P(x)\to Q)$
80183
Deduction of "Disjunction elimination"
121361
Showing that $\lnot Q \lor (\lnot Q \land R) = \lnot Q$ without a truth table
32009
Prove $\;\big((p\rightarrow q) \lor (p \rightarrow r)\big) \rightarrow (q\lor r)\equiv p \lor q \lor r$ without use of a truth table.
77507
Induction without a base case
50804
It seems obvious, but how to prove it formally?
148239
natural deduction proof with De Morgan's laws
32244
Propositional Logic - Deduction
87928
Proof of logical equivalence of biconditional and other proposition
127468
Prove that there is only one unique base b representation of any natural number.
35427
Natural Deduction - How to define literals?