 reserve Rseq, Rseq1, Rseq2 for Function of [:NAT,NAT:],REAL;

theorem
for C,D,E being non empty set, f being Function of [:C,D:],E holds
 ex g being Function of [:D,C:],E st
  for d being Element of D, c being Element of C holds g.(d,c) = f.(c,d)
proof
   let C,D,E be non empty set;
   let f be Function of [:C,D:],E;
   deffunc F(Element of D,Element of C) = f.($2,$1);
   consider IT be Function of [:D,C:],E such that
A1: for d being Element of D, c being Element of C holds IT.(d,c) = F(d,c)
      from STACKS_1:sch 2;
   take IT;
   thus thesis by A1;
end;
