reserve a,b,c,d for Real;
reserve r,s for Real;

theorem
  0 < a implies a/4 < a
proof
  assume
A1: 0 < a;
  then
A2: 0+a/4 < a/4+a/4 by Lm10;
  then a/4 < a/4+a/4+a/4 by A1,Lm10;
  then a/4+a/4 < a/4+a/4+a/4+a/4 by Lm10;
  hence thesis by A2,XXREAL_0:2;
end;
