reserve n,m,k for Element of NAT;
reserve x, X,X1,Z,Z1 for set;
reserve s,g,r,p,x0,x1,x2 for Real;
reserve s1,s2,q1 for Real_Sequence;
reserve Y for Subset of REAL;
reserve f,f1,f2 for PartFunc of REAL,REAL;

theorem Th48:
  for a,b being Real holds AffineMap(a,b).0 = b
proof
  let a,b be Real;
  thus AffineMap(a,b).0 = a*0 + b by Def4
    .= b;
end;
