Expression of type Conditional

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

# build up the expression from sub-expressions
expr = 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())

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

stored_expr.style_options()

name	description	default	current value	related methods
condition_delimiter	'comma' or 'and'	comma	comma	('with_comma_delimiter', 'with_conjunction_delimiter')

# display the expression information
stored_expr.expr_info()

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