% Mizar problem: t56_zfmisc_1,zfmisc_1,774,25 
fof(t56_zfmisc_1,conjecture,(
    ! [A,B] : 
      ( ~ r2_hidden(A,B)
     => r1_xboole_0(k1_tarski(A),B) ) ),
    inference(mizar_bg_added,[status(thm)],[symmetry_r1_xboole_0,antisymmetry_r2_hidden,dt_k1_tarski,l28_zfmisc_1]),
    [file(zfmisc_1,t56_zfmisc_1)]).

fof(symmetry_r1_xboole_0,axiom,(
    ! [A,B] : 
      ( r1_xboole_0(A,B)
     => r1_xboole_0(B,A) ) ),
    file(xboole_0,r1_xboole_0),
    []).

fof(antisymmetry_r2_hidden,axiom,(
    ! [A,B] : 
      ( r2_hidden(A,B)
     => ~ r2_hidden(B,A) ) ),
    file(hidden,r2_hidden),
    []).

fof(dt_k1_tarski,axiom,(
    $true ),
    file(tarski,k1_tarski),
    []).

fof(l28_zfmisc_1,axiom,(
    ! [A,B] : 
      ( ~ r2_hidden(A,B)
     => r1_xboole_0(k1_tarski(A),B) ) ),
    file(zfmisc_1,l28_zfmisc_1),
    []).