Metamath Proof Explorer


Theorem pw2en

Description: The power set of a set is equinumerous to set exponentiation with a base of ordinal 2. Proposition 10.44 of TakeutiZaring p. 96. This is Metamath 100 proof #52. (Contributed by NM, 29-Jan-2004) (Proof shortened by Mario Carneiro, 1-Jul-2015)

Ref Expression
Hypothesis pw2en.1
|- A e. _V
Assertion pw2en
|- ~P A ~~ ( 2o ^m A )

Proof

Step Hyp Ref Expression
1 pw2en.1
 |-  A e. _V
2 pw2eng
 |-  ( A e. _V -> ~P A ~~ ( 2o ^m A ) )
3 1 2 ax-mp
 |-  ~P A ~~ ( 2o ^m A )