import proveit
# Prepare this notebook for defining the axioms of a theory:
%axioms_notebook # Keep this at the top following 'import proveit'.
from proveit import x
from proveit.logic import Equals, Forall
from proveit.numbers import two, Abs, Exp, Real, sqrt
%begin axioms
# this axiom might be shifted to theorems once we have
# the Conditional class to use for a piece-wise definition
abs_val_def_sqrt = Forall(
x,
Equals(Abs(x), sqrt(Exp(x, two))),
domain = Real)
%end axioms