% Mizar problem: t42_rewrite1,rewrite1,860,29 
fof(t42_rewrite1,conjecture,(
    ! [A] : 
      ( v1_relat_1(A)
     => ! [B,C] : 
          ( r6_rewrite1(A,B,C)
         => r6_rewrite1(A,C,B) ) ) ),
    inference(mizar_bg_added,[status(thm)],[d8_rewrite1]),
    [file(rewrite1,t42_rewrite1)]).

fof(d8_rewrite1,axiom,(
    ! [A] : 
      ( v1_relat_1(A)
     => ! [B,C] : 
          ( r6_rewrite1(A,B,C)
        <=> ? [D] : 
              ( r1_rewrite1(A,D,B)
              & r1_rewrite1(A,D,C) ) ) ) ),
    file(rewrite1,d8_rewrite1),
    []).