SOLUTION: Why is the cardinality of the empty set { Ø } equal zero?

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Question 1208676: Why is the cardinality of the empty set { Ø } equal zero?
Found 3 solutions by ikleyn, greenestamps, math_tutor2020:
Answer by ikleyn(52776)   (Show Source):
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The cardinality of the empty set is zero, because the empty set has zero elements.

All these profound exercises about empty set remind me
the expression "treading water in a mortar".

Answer by greenestamps(13198)   (Show Source):
You can put this solution on YOUR website!

The cardinality of a set is the number of elements in the set.

The number of elements in the empty set is 0, so the cardinality of the empty set is zero.

Answer by math_tutor2020(3816)   (Show Source):
You can put this solution on YOUR website!

I think you meant to say Ø instead of { Ø }
There's a slight difference between these two sets.
They are not the same.

See this page
https://math.stackexchange.com/questions/3479883/is-or-%c3%98-an-empty-set
In that link, the user MPW perhaps has the best answer.