Expression of type Lambda

from the theory of proveit.logic.booleans.implication

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 A, B, Conditional, Lambda
from proveit.logic import And, Implies, Not

# build up the expression from sub-expressions
expr = Lambda(B, Conditional(Not(A), And(Implies(A, B), Not(B))))

expr:

# 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")

Passed sanity check: expr matches stored_expr

# Show the LaTeX representation of the expression for convenience if you need it.
print(stored_expr.latex())

B \mapsto \left\{\lnot A \textrm{ if } A \Rightarrow B ,  \lnot B\right..

stored_expr.style_options()

no style options

# display the expression information
stored_expr.expr_info()

	core type	sub-expressions	expression
0	Lambda	parameter: 14 body: 1
1	Conditional	value: 2 condition: 3
2	Operation	operator: 11 operand: 13
3	Operation	operator: 5 operands: 6
4	ExprTuple	13
5	Literal
6	ExprTuple	7, 8
7	Operation	operator: 9 operands: 10
8	Operation	operator: 11 operand: 14
9	Literal
10	ExprTuple	13, 14
11	Literal
12	ExprTuple	14
13	Variable
14	Variable