Math Is Fun Forum

{7/3}

Member

Registered: 2013-02-11

Posts: 210

Tautology and contradiction

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

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

Bob

Administrator

Registered: 2010-06-20

Posts: 10,158

Re: Tautology and contradiction

hi {7/3}

try here:

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

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

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

{7/3}

Member

Registered: 2013-02-11

Posts: 210

Re: Tautology and contradiction

Okay,what are their applications

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

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: Tautology and contradiction

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

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“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

Re: Tautology and contradiction

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

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