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**Set theory**

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

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

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

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

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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**Set theory**