Expression of type Lambda

from the theory of proveit.numbers.summation

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, a, b, l
from proveit.logic import Equals, InSet
from proveit.numbers import Add, Integer, Mult, one

# build up the expression from sub-expressions
sub_expr1 = Add(l, one)
expr = Lambda(l, Conditional(Equals(Mult(a, b, sub_expr1), Mult(sub_expr1, Mult(a, b))), InSet(l, Integer)))

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())

l \mapsto \left\{\left(a \cdot b \cdot \left(l + 1\right)\right) = \left(\left(l + 1\right) \cdot \left(a \cdot b\right)\right) \textrm{ if } l \in \mathbb{Z}\right..

stored_expr.style_options()

no style options

# display the expression information
stored_expr.expr_info()

	core type	sub-expressions	expression
0	Lambda	parameter: 20 body: 2
1	ExprTuple	20
2	Conditional	value: 3 condition: 4
3	Operation	operator: 5 operands: 6
4	Operation	operator: 7 operands: 8
5	Literal
6	ExprTuple	9, 10
7	Literal
8	ExprTuple	20, 11
9	Operation	operator: 18 operands: 12
10	Operation	operator: 18 operands: 13
11	Literal
12	ExprTuple	22, 23, 14
13	ExprTuple	14, 15
14	Operation	operator: 16 operands: 17
15	Operation	operator: 18 operands: 19
16	Literal
17	ExprTuple	20, 21
18	Literal
19	ExprTuple	22, 23
20	Variable
21	Literal
22	Variable
23	Variable