Expression of type Lambda

from the theory of proveit.logic.equality

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, Lambda, P, Px, Py, x, y
from proveit.logic import And, Equals

# build up the expression from sub-expressions
expr = Lambda([P, x, y], Conditional(Px, And(Py, Equals(x, y))))

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())

\left(P, x, y\right) \mapsto \left\{P\left(x\right) \textrm{ if } P\left(y\right) ,  x = y\right..

stored_expr.style_options()

no style options

# display the expression information
stored_expr.expr_info()

	core type	sub-expressions	expression
0	Lambda	parameters: 1 body: 2
1	ExprTuple	10, 14, 15
2	Conditional	value: 3 condition: 4
3	Operation	operator: 10 operand: 14
4	Operation	operator: 6 operands: 7
5	ExprTuple	14
6	Literal
7	ExprTuple	8, 9
8	Operation	operator: 10 operand: 15
9	Operation	operator: 12 operands: 13
10	Variable
11	ExprTuple	15
12	Literal
13	ExprTuple	14, 15
14	Variable
15	Variable