% Mizar problem: l6_jordan1d,jordan1d,76,5 
fof(l6_jordan1d, conjecture,  (! [A] :  (! [B] :  (! [C] :  (! [D] : k3_tarski(k2_enumset1(A, B, C, D))=k2_xboole_0(k2_xboole_0(k2_xboole_0(A, B), C), D)) ) ) ) ).
fof(antisymmetry_r2_hidden, axiom,  (! [A, B] :  (r2_hidden(A, B) =>  ~ (r2_hidden(B, A)) ) ) ).
fof(asymmetry_r2_tarski, axiom,  (! [A, B] :  (r2_tarski(A, B) =>  ~ (r2_tarski(B, A)) ) ) ).
fof(commutativity_k2_xboole_0, axiom,  (! [A, B] : k2_xboole_0(A, B)=k2_xboole_0(B, A)) ).
fof(d10_xboole_0, axiom,  (! [A] :  (! [B] :  (A=B <=>  (r1_tarski(A, B) & r1_tarski(B, A)) ) ) ) ).
fof(d2_enumset1, axiom,  (! [A] :  (! [B] :  (! [C] :  (! [D] :  (! [E] :  (E=k2_enumset1(A, B, C, D) <=>  (! [F] :  (r2_hidden(F, E) <=>  ~ ( ( ~ (F=A)  &  ( ~ (F=B)  &  ( ~ (F=C)  &  ~ (F=D) ) ) ) ) ) ) ) ) ) ) ) ) ).
fof(d3_tarski, axiom,  (! [A] :  (! [B] :  (r1_tarski(A, B) <=>  (! [C] :  (r2_hidden(C, A) => r2_hidden(C, B)) ) ) ) ) ).
fof(d4_tarski, axiom,  (! [A] :  (! [B] :  (B=k3_tarski(A) <=>  (! [C] :  (r2_hidden(C, B) <=>  (? [D] :  (r2_hidden(C, D) & r2_hidden(D, A)) ) ) ) ) ) ) ).
fof(dt_k1_zfmisc_1, axiom, $true).
fof(dt_k2_enumset1, axiom, $true).
fof(dt_k2_xboole_0, axiom, $true).
fof(dt_k3_tarski, axiom, $true).
fof(dt_m1_subset_1, axiom, $true).
fof(existence_m1_subset_1, axiom,  (! [A] :  (? [B] : m1_subset_1(B, A)) ) ).
fof(idempotence_k2_xboole_0, axiom,  (! [A, B] : k2_xboole_0(A, A)=A) ).
fof(l5_jordan1d, axiom,  (! [A] :  (! [B] :  (! [C] :  (! [D] :  (! [E] :  (r2_tarski(A, k2_xboole_0(k2_xboole_0(k2_xboole_0(B, C), D), E)) <=>  ~ ( ( ~ (r2_tarski(A, B))  &  ( ~ (r2_tarski(A, C))  &  ( ~ (r2_tarski(A, D))  &  ~ (r2_tarski(A, E)) ) ) ) ) ) ) ) ) ) ) ).
fof(redefinition_r2_tarski, axiom,  (! [A, B] :  (r2_tarski(A, B) <=> r2_hidden(A, B)) ) ).
fof(reflexivity_r1_tarski, axiom,  (! [A, B] : r1_tarski(A, A)) ).
fof(t1_subset, axiom,  (! [A] :  (! [B] :  (r2_tarski(A, B) => m1_subset_1(A, B)) ) ) ).
fof(t3_subset, axiom,  (! [A] :  (! [B] :  (m1_subset_1(A, k1_zfmisc_1(B)) <=> r1_tarski(A, B)) ) ) ).
fof(t4_subset, axiom,  (! [A] :  (! [B] :  (! [C] :  ( (r2_tarski(A, B) & m1_subset_1(B, k1_zfmisc_1(C)))  => m1_subset_1(A, C)) ) ) ) ).
