% Mizar problem: t91_mcart_1,mcart_1,1385,7 
fof(t91_mcart_1, conjecture,  (! [A] :  (! [B] :  (! [C] :  (! [D] :  (! [E] :  (! [F] : k9_xtuple_0(k9_xtuple_0(k2_tarski(k3_xtuple_0(A, B, C), k3_xtuple_0(D, E, F))))=k2_tarski(A, D)) ) ) ) ) ) ).
fof(cc1_xtuple_0, axiom,  (! [A] :  (v2_xtuple_0(A) => v1_xtuple_0(A)) ) ).
fof(commutativity_k2_tarski, axiom,  (! [A, B] : k2_tarski(A, B)=k2_tarski(B, A)) ).
fof(d4_xtuple_0, axiom,  (! [A] :  (! [B] :  (! [C] : k3_xtuple_0(A, B, C)=k4_tarski(k4_tarski(A, B), C)) ) ) ).
fof(d5_tarski, axiom,  (! [A] :  (! [B] : k4_tarski(A, B)=k2_tarski(k2_tarski(A, B), k1_tarski(A))) ) ).
fof(dt_k10_xtuple_0, axiom, $true).
fof(dt_k1_tarski, axiom, $true).
fof(dt_k2_tarski, axiom, $true).
fof(dt_k3_xtuple_0, axiom, $true).
fof(dt_k4_tarski, axiom, $true).
fof(dt_k9_xtuple_0, axiom, $true).
fof(fc1_xtuple_0, axiom,  (! [A, B] : v1_xtuple_0(k4_tarski(A, B))) ).
fof(fc2_xtuple_0, axiom,  (! [A, B, C] : v2_xtuple_0(k3_xtuple_0(A, B, C))) ).
fof(fc5_relat_1, axiom,  (! [A, B] : v1_relat_1(k1_tarski(k4_tarski(A, B)))) ).
fof(fc7_relat_1, axiom,  (! [A, B, C, D] : v1_relat_1(k2_tarski(k4_tarski(A, B), k4_tarski(C, D)))) ).
fof(rc1_xtuple_0, axiom,  (? [A] : v1_xtuple_0(A)) ).
fof(rc2_xtuple_0, axiom,  (? [A] : v2_xtuple_0(A)) ).
fof(t10_relat_1, axiom,  (! [A] :  (! [B] :  (! [C] :  (! [D] :  (k9_xtuple_0(k2_tarski(k4_tarski(A, B), k4_tarski(C, D)))=k2_tarski(A, C) & k10_xtuple_0(k2_tarski(k4_tarski(A, B), k4_tarski(C, D)))=k2_tarski(B, D)) ) ) ) ) ).
