# Math Help - Did I do this proof correct?

1. ## Did I do this proof correct?

Prove or Disprove

Given: For every nonempty set A, there exists a set B such that l A-B l = l B-A l.

Proof: Statement is true. Let A not equal an empty set. Then let B=A. Then A-B=B-A=empty set. So l A-B l = l B-A l = 0.

2. Originally Posted by Possible actuary
Prove or Disprove

Given: For every nonempty set A, there exists a set B such that l A-B l = l B-A l.

Proof: Statement is true. Let A not equal an empty set. Then let B=A. Then A-B=B-A=empty set. So l A-B l = l B-A l = 0.
Seems ok to me