Metamath Proof Explorer


Theorem lidlbas

Description: A (left) ideal of a ring is the base set of the restriction of the ring to this ideal. (Contributed by AV, 17-Feb-2020)

Ref Expression
Hypotheses lidlabl.l
|- L = ( LIdeal ` R )
lidlabl.i
|- I = ( R |`s U )
Assertion lidlbas
|- ( U e. L -> ( Base ` I ) = U )

Proof

Step Hyp Ref Expression
1 lidlabl.l
 |-  L = ( LIdeal ` R )
2 lidlabl.i
 |-  I = ( R |`s U )
3 eqid
 |-  ( Base ` R ) = ( Base ` R )
4 2 3 ressbas
 |-  ( U e. L -> ( U i^i ( Base ` R ) ) = ( Base ` I ) )
5 3 1 lidlss
 |-  ( U e. L -> U C_ ( Base ` R ) )
6 df-ss
 |-  ( U C_ ( Base ` R ) <-> ( U i^i ( Base ` R ) ) = U )
7 5 6 sylib
 |-  ( U e. L -> ( U i^i ( Base ` R ) ) = U )
8 4 7 eqtr3d
 |-  ( U e. L -> ( Base ` I ) = U )