reserve x,X,Y for set;
reserve C for non empty set;
reserve c for Element of C;
reserve V for RealNormSpace;
reserve f,f1,f2,f3 for PartFunc of C,V;
reserve r,r1,r2,p for Real;

theorem
  for V being add-associative right_zeroed right_complementable Abelian
    scalar-distributive scalar-unital scalar-associative vector-distributive
    non empty RLSStruct
  for f1,f2 being PartFunc of C,V holds
  f1 - (-f2) = f1 + f2
proof
  let V be add-associative right_zeroed right_complementable Abelian
  scalar-distributive scalar-unital scalar-associative vector-distributive
  non empty RLSStruct;
  let f1,f2 be PartFunc of C,V;
  thus f1 - (-f2) = f1 + (-(-f2)) by Th25
    .= f1 + f2 by Th24;
end;
