If tm is a term of type bool, a call new_open_axiom("name",tm) creates
a theorem
|- tm
and stores it away in the current theory.
FAILURE
Fails if HOL is not in draft mode, or there is already an axiom or definition
of that name in the current theory, or it the given term does not have type
bool.
EXAMPLE
- new_theory "gurk";
() : unit
- new_axiom("untrue",--`x = 1`--));
|- x = 1
COMMENTS
For most purposes, it is unnecessary to declare new axioms: all of classical
mathematics can be derived by definitional extension alone. Proceeding
by definition is not only more elegant, but also guarantees the
consistency of the deductions made. However, there are certain entities
which cannot be modelled in simple type theory without further axioms,
such as higher transfinite ordinals.