Grzegorz Bancerek wrote: > Second, > "x is irrational", "not x is rational", "x is not irrational", > "x is not non rational", "not x is non rational" > All these have the same internal representation. Sorry, I mistaken. x is irrational, not x is rational, x is not rational, not x is non irrational, x is not non irrational, x is non rational, not x is not non rational Best, Grzegorz