import proveit
# Automation is not needed when building an expression:
proveit.defaults.automation = False # This will speed things up.
proveit.defaults.inline_pngs = False # Makes files smaller.
%load_expr # Load the stored expression as 'stored_expr'
# import Expression classes needed to build the expression
from proveit import Conditional, ExprTuple, Lambda, a, x, y
from proveit.logic import And, Equals, InSet
from proveit.numbers import Add, Natural
# build up the expression from sub-expressions
expr = ExprTuple(Lambda([a, x, y], Conditional(Equals(Add(a, x), Add(a, y)), And(InSet(a, Natural), InSet(x, Natural), InSet(y, Natural), Equals(x, y)))))
# check that the built expression is the same as the stored expression
assert expr == stored_expr
assert expr._style_id == stored_expr._style_id
print("Passed sanity check: expr matches stored_expr")
# Show the LaTeX representation of the expression for convenience if you need it.
print(stored_expr.latex())
stored_expr.style_options()
# display the expression information
stored_expr.expr_info()