Metamath Proof Explorer


Theorem submbas

Description: The base set of a submonoid. (Contributed by Stefan O'Rear, 15-Jun-2015)

Ref Expression
Hypothesis submmnd.h
|- H = ( M |`s S )
Assertion submbas
|- ( S e. ( SubMnd ` M ) -> S = ( Base ` H ) )

Proof

Step Hyp Ref Expression
1 submmnd.h
 |-  H = ( M |`s S )
2 eqid
 |-  ( Base ` M ) = ( Base ` M )
3 2 submss
 |-  ( S e. ( SubMnd ` M ) -> S C_ ( Base ` M ) )
4 1 2 ressbas2
 |-  ( S C_ ( Base ` M ) -> S = ( Base ` H ) )
5 3 4 syl
 |-  ( S e. ( SubMnd ` M ) -> S = ( Base ` H ) )