Conversion to produce absolute value of a rational literal of type :real.
DESCRIPTION
The call REAL_RAT_ABS_CONV `abs c`, where c is a rational literal of type
:real, returns the theorem |- abs c = d where d is the canonical rational
literal that is equal to c's absolute value. The literal c may be an
integer literal (&n or -- &n), a ratio (&p / &q or -- &p / &q), or a
decimal (#DDD.DDDD or #DDD.DDDDeNN). The returned value d is always put
in the form &p / &q or -- &p / &q with q > 1 and p and q sharing no
common factor, or simply &p or -- &p when that is impossible.
FAILURE CONDITIONS
Fails if applied to a term that is not the absolute value function applied to
one of the permitted forms of rational literal of type :real.