ILE Home Intuitionistic Logic Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  ILE Home  >  Th. List  >  eleq2w Unicode version

Theorem eleq2w 2291
Description: Weaker version of eleq2 2293 (but more general than elequ2 2205) not depending on ax-ext 2211 nor df-cleq 2222. (Contributed by BJ, 29-Sep-2019.)
Assertion
Ref Expression
eleq2w  |-  ( x  =  y  ->  ( A  e.  x  <->  A  e.  y ) )

Proof of Theorem eleq2w
Dummy variable  z is distinct from all other variables.
StepHypRef Expression
1 elequ2 2205 . . . 4  |-  ( x  =  y  ->  (
z  e.  x  <->  z  e.  y ) )
21anbi2d 464 . . 3  |-  ( x  =  y  ->  (
( z  =  A  /\  z  e.  x
)  <->  ( z  =  A  /\  z  e.  y ) ) )
32exbidv 1871 . 2  |-  ( x  =  y  ->  ( E. z ( z  =  A  /\  z  e.  x )  <->  E. z
( z  =  A  /\  z  e.  y ) ) )
4 df-clel 2225 . 2  |-  ( A  e.  x  <->  E. z
( z  =  A  /\  z  e.  x
) )
5 df-clel 2225 . 2  |-  ( A  e.  y  <->  E. z
( z  =  A  /\  z  e.  y ) )
63, 4, 53bitr4g 223 1  |-  ( x  =  y  ->  ( A  e.  x  <->  A  e.  y ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 104    <-> wb 105    = wceq 1395   E.wex 1538    e. wcel 2200
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1493  ax-gen 1495  ax-ie1 1539  ax-ie2 1540  ax-8 1550  ax-4 1556  ax-17 1572  ax-i9 1576  ax-ial 1580  ax-14 2203
This theorem depends on definitions:  df-bi 117  df-clel 2225
This theorem is referenced by:  exmidontriimlem4  7406  umgr2edgneu  16010  uspgredg2v  16019
  Copyright terms: Public domain W3C validator