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, fa, fx, x
from proveit.logic import Equals, InSet
from proveit.numbers import Integer, Interval, Sum

# build up the expression from sub-expressions
expr = Lambda(a, Conditional(Equals(Sum(index_or_indices = [x], summand = fx, domain = Interval(a, a)), fa), InSet(a, 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())

a \mapsto \left\{\left(\sum_{x = a}^{a} f\left(x\right)\right) = f\left(a\right) \textrm{ if } a \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: 25 body: 1
1	Conditional	value: 2 condition: 3
2	Operation	operator: 4 operands: 5
3	Operation	operator: 19 operands: 6
4	Literal
5	ExprTuple	7, 8
6	ExprTuple	25, 9
7	Operation	operator: 10 operand: 13
8	Operation	operator: 17 operand: 25
9	Literal
10	Literal
11	ExprTuple	13
12	ExprTuple	25
13	Lambda	parameter: 21 body: 14
14	Conditional	value: 15 condition: 16
15	Operation	operator: 17 operand: 21
16	Operation	operator: 19 operands: 20
17	Variable
18	ExprTuple	21
19	Literal
20	ExprTuple	21, 22
21	Variable
22	Operation	operator: 23 operands: 24
23	Literal
24	ExprTuple	25, 25
25	Variable