Metamath Proof Explorer


Theorem dom0

Description: A set dominated by the empty set is empty. (Contributed by NM, 22-Nov-2004) Avoid ax-pow , ax-un . (Revised by BTernaryTau, 29-Nov-2024)

Ref Expression
Assertion dom0 A A =

Proof

Step Hyp Ref Expression
1 brdomi A f f : A 1-1
2 f1f f : A 1-1 f : A
3 f00 f : A f = A =
4 3 simprbi f : A A =
5 2 4 syl f : A 1-1 A =
6 5 exlimiv f f : A 1-1 A =
7 1 6 syl A A =
8 en0 A A =
9 endom A A
10 8 9 sylbir A = A
11 7 10 impbii A A =