theorem Th37:
  d in dom(SC_Fsuperpos(f,g,v)) implies
   SC_Fsuperpos(f,g,v).d = f.local_overlapping(V,A,d,g.d,v) & d in dom g
  proof
    set F = SC_Fsuperpos(f,g,v);
    assume
A1: d in dom(F);
    dom(F) = {d where d is TypeSCNominativeData of V,A:
    local_overlapping(V,A,d,g.d,v) in dom f & d in dom g} by Def15;
    then
A2: ex d1 being TypeSCNominativeData of V,A st d1 = d &
    (local_overlapping(V,A,d1,g.d1,v) in dom f & d1 in dom g) by A1;
    F,d =~ f,local_overlapping(V,A,d,g.d,v) by A2,Def15;
    hence thesis by A2;
  end;
