% Mizar problem: l10_ens_1,ens_1,190,5 
fof(l10_ens_1, conjecture,  (! [A] :  (! [B] :  (! [C] :  (! [D] :  (! [E] :  (! [F] :  (k4_tarski(k4_tarski(A, C), E)=k4_tarski(k4_tarski(B, D), F) =>  (A=B & C=D) ) ) ) ) ) ) ) ).
fof(dt_k4_tarski, axiom, $true).
fof(fc1_xtuple_0, axiom,  (! [A, B] : v1_xtuple_0(k4_tarski(A, B))) ).
fof(rc1_xtuple_0, axiom,  (? [A] : v1_xtuple_0(A)) ).
fof(t1_xtuple_0, axiom,  (! [A] :  (! [B] :  (! [C] :  (! [D] :  (k4_tarski(A, B)=k4_tarski(C, D) =>  (A=C & B=D) ) ) ) ) ) ).
