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# Is a set a subset of itself?

From Mathematics Is A Science

Jump to navigationJump to search**Question:** Is a set a subset of itself?

**Answer:** Yes.

**Why:** Along with another improper subset, the empty set. If in doubt, (always!) consider the definition: a set $A$ is a subset of $B$ if every element of $A$ is also an element of $B$. This is certainly true if $A=B$. $\blacksquare$