Question

Help, have to prove the tautology (p ∨ ¬p) from nothing using fitch system.

score 181 · Answer 1 · 2026-03-26 09:17:41

Help, have to prove the tautology (p ∨ ¬p) from nothing using fitch system.

Published on 26 Mar 2026 - 9:17

score 37 · Answer 2 · 2020-05-04 21:46:30

I want to prove $P$ is true (by contradiction). What happens if I deduce $Q$ from $\lnot P$, knowing $\lnot Q$, then replace $Q$ with $P$?

score 256 · Answer 3 · 2026-03-29 04:48:06

256

Views

Understanding how to prove either/or type statements in logic

Published on 29 Mar 2026 - 4:48

score 812 · Answer 4 · 2026-02-23 04:57:25

812

Views

Proving $\vdash \neg \neg P \to P$ (double negation elimination) in first order logic, preferrably without deduction theorem

Published on 23 Feb 2026 - 4:57

score 234 · Answer 5 · 2020-05-07 09:04:50

234

Views

I found that resolution is not complete: what do I miss?

Published on 07 May 2020 - 9:04

score 145 · Answer 6 · 2026-03-25 15:47:58

145

Views

Propositional and First Order Logic Tool to analyse formula

Published on 25 Mar 2026 - 15:47

score 77 · Answer 7 · 2026-03-25 06:08:28

77

Views

Question about MU puzzle from GEB

Published on 25 Mar 2026 - 6:08

score 38 · Answer 8 · 2020-05-09 22:41:25

38

Views

Trichotomy and Xor - odd results

Published on 09 May 2020 - 22:41

score 40 · Answer 9 · 2020-05-11 05:49:26

40

Views

finding CNF and a logically Logically equivalent DNF for Propositional form (p→(q→r))

Published on 11 May 2020 - 5:49

score 599 · Answer 10 · 2026-03-31 22:24:01

599

Views

Logically, deductively, tautologically, semantically, syntactically valid arguments, what is the difference?

Published on 31 Mar 2026 - 22:24

score 102 · Answer 11 · 2020-05-11 17:17:24

102

Views

Derivation of $\text{A} \vee \neg{\text{A}}$ without a premise.

Published on 11 May 2020 - 17:17

score 98 · Answer 12 · 2026-03-25 15:50:22

98

Views

Write a statement in propositional logic that says $x \in A Δ B$. Solution should use at most two connectives.

Published on 25 Mar 2026 - 15:50

score 304 · Answer 13 · 2026-04-05 23:15:40

304

Views

Are inference rules just tautologically (or syntactically) valid arguments?

Published on 05 Apr 2026 - 23:15

score 17 · Answer 14 · 2020-05-12 13:51:23

17

Views

Dual of Propositional Formula

Published on 12 May 2020 - 13:51

score 650 · Answer 15 · 2026-03-26 12:05:48

650

Views

Construct a proof for the argument: P ∨ Q, ¬Q ∴ P

Published on 26 Mar 2026 - 12:05

List Question

Help, have to prove the tautology (p ∨ ¬p) from nothing using fitch system.

I want to prove $P$ is true (by contradiction). What happens if I deduce $Q$ from $\lnot P$, knowing $\lnot Q$, then replace $Q$ with $P$?

Understanding how to prove either/or type statements in logic

Proving $\vdash \neg \neg P \to P$ (double negation elimination) in first order logic, preferrably without deduction theorem

I found that resolution is not complete: what do I miss?

Propositional and First Order Logic Tool to analyse formula

Question about MU puzzle from GEB

Trichotomy and Xor - odd results

finding CNF and a logically Logically equivalent DNF for Propositional form (p→(q→r))

Logically, deductively, tautologically, semantically, syntactically valid arguments, what is the difference?

Derivation of $\text{A} \vee \neg{\text{A}}$ without a premise.

Write a statement in propositional logic that says $x \in A Δ B$. Solution should use at most two connectives.

Are inference rules just tautologically (or syntactically) valid arguments?

Dual of Propositional Formula

Construct a proof for the argument: P ∨ Q, ¬Q ∴ P

Trending Questions

Popular # Hahtags

Popular Questions