
theorem Th6:
  for L be antisymmetric transitive with_infima RelStr for a,b,c be
  Element of L holds a <= b implies a"/\"c <= b"/\"c
proof
  let L be antisymmetric transitive with_infima RelStr;
  let a,b,c be Element of L;
A1: a"/\"c <= a by YELLOW_0:23;
A2: a"/\"c <= c by YELLOW_0:23;
  assume a <= b;
  then a"/\"c <= b by A1,YELLOW_0:def 2;
  hence thesis by A2,YELLOW_0:23;
end;
