Expression of type Lambda

from the theory of proveit.logic.sets.enumeration

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 Lambda, x
from proveit.core_expr_types import y_1_to_n
from proveit.logic import Boolean, InSet, Set

# build up the expression from sub-expressions
expr = Lambda([x, y_1_to_n], InSet(InSet(x, Set(y_1_to_n)), Boolean))

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(x, y_{1}, y_{2}, \ldots, y_{n}\right) \mapsto \left(\left(x \in \left\{y_{1}, y_{2}, \ldots, y_{n}\right\}\right) \in \mathbb{B}\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	8, 12
2	Operation	operator: 6 operands: 3
3	ExprTuple	4, 5
4	Operation	operator: 6 operands: 7
5	Literal
6	Literal
7	ExprTuple	8, 9
8	Variable
9	Operation	operator: 10 operands: 11
10	Literal
11	ExprTuple	12
12	ExprRange	lambda_map: 13 start_index: 14 end_index: 15
13	Lambda	parameter: 19 body: 16
14	Literal
15	Variable
16	IndexedVar	variable: 17 index: 19
17	Variable
18	ExprTuple	19
19	Variable