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, Function, Lambda, a, b, f, x
from proveit.logic import InSet
from proveit.numbers import Interval, Neg

# build up the expression from sub-expressions
expr = Lambda(x, Conditional(Function(f, [Neg(x)]), InSet(x, Interval(Neg(b), Neg(a)))))

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())

x \mapsto \left\{f\left(-x\right) \textrm{ if } x \in \{-b~\ldotp \ldotp~-a\}\right..

stored_expr.style_options()

no style options

# display the expression information
stored_expr.expr_info()

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