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#1 2012-05-04 06:42:35

juantheron
Member
Registered: 2011-10-19
Posts: 312

no of onto function

If a Set A consists of n- distinct elements, then total no. of onto function from A to A is

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#2 2012-05-04 06:49:31

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 16,049

Re: no of onto function

Because it is the same as the number of bijections from A to A,it will be n!


“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
The knowledge of some things as a function of age is a delta function.

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#3 2012-05-04 06:54:26

juantheron
Member
Registered: 2011-10-19
Posts: 312

Re: no of onto function

yes

would you like to explain it to me

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#4 2012-05-04 06:57:24

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 16,049

Re: no of onto function

Do you understand why it is a bijection?


“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
The knowledge of some things as a function of age is a delta function.

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#5 2012-05-04 07:14:33

juantheron
Member
Registered: 2011-10-19
Posts: 312

Re: no of onto function

no

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#6 2012-05-04 07:29:37

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 16,049

Re: no of onto function

If you had two elements that give us the same value,then there must be one of the other elements must give us two different values,which is a contradiction with the definition of a function. So all elements have there own value i.e. no two elements give us the same value of the function.This is the definition of a one-to-one function,and because it is an onto function,it is a bijection.


“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
The knowledge of some things as a function of age is a delta function.

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