 reserve X,a,b,c,x,y,z,t for set;
 reserve R for Relation;

theorem Corr4: :: Corollary 4
  for R1, R2 being non empty RelStr st
    the carrier of R1 = the carrier of R2 &
    LAp R1 = LAp R2 holds
      the InternalRel of R2 = the InternalRel of R1
  proof
    let R1, R2 be non empty RelStr;
    assume
A1: the carrier of R1 = the carrier of R2 &
    LAp R1 = LAp R2;
    the InternalRel of R2 c= the InternalRel of R1 &
    the InternalRel of R1 c= the InternalRel of R2 by Prop18,A1;
    hence thesis by XBOOLE_0:def 10;
  end;
