### O-FIRST-EXPT

the first exponent of an ordinal
Major Section: ACL2-BUILT-INS

An ACL2 ordinal is either a natural number or, for an infinite ordinal, a
list whose elements are exponent-coefficient pairs (see o-p). In the latter
case, this function returns the `car`

of the first pair in the list. In
the case of a natural number, the value returned is 0 (since a natural
number, `n`

, can be thought of as (w^0)n).

For the corresponding coefficient, see o-first-coeff.

To see the ACL2 definition of this function, see pf.