
theorem Th31:
  for C being Category, a,b,c being Object of C, f,g being
Morphism of C st f in Hom(a,b) & g in Hom(b,c) holds Den(compsym(a,b,c), MSAlg
  C).<*g,f*> = g(*)f
proof
  let C be Category, a,b,c be Object of C, f,g be Morphism of C;
  assume that
A1: f in Hom(a,b) and
A2: g in Hom(b,c);
A3: dom g = b & cod g = c by A2,CAT_1:1;
  dom f = a & cod f = b by A1,CAT_1:1;
  hence thesis by A3,Def13;
end;
