set M = ModelSP (Inf_seq S);
deffunc H₁( Element of ModelSP (Inf_seq S), Element of ModelSP (Inf_seq S)) -> Element of ModelSP (Inf_seq S) = And_0 ($1,$2,S);
consider o being BinOp of (ModelSP (Inf_seq S)) such that
A1: for f, g being Element of ModelSP (Inf_seq S) holds o . (f,g) = H₁(f,g) from BINOP_1:sch 4();
for f, g being set st f in ModelSP (Inf_seq S) & g in ModelSP (Inf_seq S) holds
o . (f,g) = And_0 (f,g,S) by A1;
hence ex b₁ being BinOp of (ModelSP (Inf_seq S)) st
for f, g being set st f in ModelSP (Inf_seq S) & g in ModelSP (Inf_seq S) holds
b₁ . (f,g) = And_0 (f,g,S) ; :: thesis: verum