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## #1 2019-10-22 15:43:52

666 bro
Member
From: Flatland
Registered: 2019-04-26
Posts: 580

### Set theory

How could a null set be an subset of the given set A?

"An equation for me has no meaning, unless it expresses a thought of God"- Srinivasa ramanujan

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## #2 2019-10-22 19:37:20

Bob
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Registered: 2010-06-20
Posts: 8,913

### Re: Set theory

hi 666 bro

Introduce a second set B that does not intersect A.

A intersect B = null set, so the null set must be in A and in B.

This might seem to be just playing with non existent sets but it's safer to assume this is true than trying to re-write the whole of set theory.

Bob

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

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## #3 2020-01-27 01:05:28

666 bro
Member
From: Flatland
Registered: 2019-04-26
Posts: 580

### Re: Set theory

What would happen if we do union of given set A and an empty set  ?

"An equation for me has no meaning, unless it expresses a thought of God"- Srinivasa ramanujan

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## #4 2020-01-27 06:24:17

Bob
Administrator
Registered: 2010-06-20
Posts: 8,913

### Re: Set theory

What would you have if you had 10 dollars and nothing?

Bob

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

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