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**{7/3}****Member**- Registered: 2013-02-11
- Posts: 210

I do not understand the concept of tautology and contradiction in logic,can anybody help?

There are 10 kinds of people in the world,people who understand binary and people who don't.

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,269

hi {7/3}

try here:

http://en.wikipedia.org/wiki/Tautology_(logic)

http://en.wikipedia.org/wiki/Contradiction

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**{7/3}****Member**- Registered: 2013-02-11
- Posts: 210

Okay,what are their applications

There are 10 kinds of people in the world,people who understand binary and people who don't.

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 14,885

Well, contradiction is used for proving things in math. It's one of the major methods of proof besides the proof by induction.

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

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**{7/3}****Member**- Registered: 2013-02-11
- Posts: 210

Okay,what about tautology?and contradiction in proofs is only used in the form -p and (not p)

There are 10 kinds of people in the world,people who understand binary and people who don't.

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