From 0aa89d91f0cc8f35b8aeaeecca2558b6779c241a Mon Sep 17 00:00:00 2001 From: mkoument Date: Sat, 24 Nov 2018 03:37:41 +0200 Subject: [PATCH] Added definition about contradiction (#30310) * Added definition about contradiction * Update index.md --- guide/english/logic/tautologies/index.md | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/guide/english/logic/tautologies/index.md b/guide/english/logic/tautologies/index.md index 66620ea3ca..9b37954b2b 100644 --- a/guide/english/logic/tautologies/index.md +++ b/guide/english/logic/tautologies/index.md @@ -4,6 +4,8 @@ title: Tautologies ## Tautologies ### Definition In logic, a tautology is a statement that is true in every possible case. The opposite of a tautology is a contradiction, a statement being false in every possible cases. +Also, a formula is said to be a contradiciotn if every truth assignment to its component statements results in the formula being false. + ### Example @@ -52,6 +54,7 @@ The arrow simply means "implies". p implies p OR q, it can also mean if...the #### More Information: -[Wikipedia Tautology (Logic)](https://en.wikipedia.org/wiki/Tautology_(logic)) -[Youtube Truth Tables](https://www.youtube.com/watch?v=O0KbymjE7xU) -[Wikipedia Logic Symbols](https://en.wikipedia.org/wiki/List_of_logic_symbols) \ No newline at end of file +- [Wikipedia Tautology (Logic)](https://en.wikipedia.org/wiki/Tautology_(logic)) +- [Youtube Truth Tables](https://www.youtube.com/watch?v=O0KbymjE7xU) +- [Wikipedia Logic Symbols](https://en.wikipedia.org/wiki/List_of_logic_symbols) +- [Mathonline, Tautologies and Contradictions](http://mathonline.wikidot.com/tautologies-and-contradictions)