
theorem
  for a,b be non weightless positive Real st
  log (a,b) >= 1 holds 0 < log (b,a) <= 1
  proof
    let a,b be non weightless positive Real;
    assume
    A2: log (a,b) >= 1;
    (log (a,b))/(log (a,b)) >= 1/(log (a,b)) by A2,XREAL_1:72; then
    1 >= 1/log (a,b) by A2,XCMPLX_1:60;
    hence thesis by A2,ABA;
  end;
