Expression of type Conditional

from the theory of proveit.numbers.negation

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, a, b, c
from proveit.logic import And, Equals, InSet
from proveit.numbers import Add, Natural, subtract

# build up the expression from sub-expressions
expr = Conditional(Equals(subtract(c, a), b), And(InSet(a, Natural), InSet(b, Natural), InSet(c, Natural), Equals(Add(a, b), c)))

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\{\left(c - a\right) = b \textrm{ if } a \in \mathbb{N} ,  b \in \mathbb{N} ,  c \in \mathbb{N} ,  \left(a + b\right) = c\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: 16 operands: 3
2	Operation	operator: 4 operands: 5
3	ExprTuple	6, 27
4	Literal
5	ExprTuple	7, 8, 9, 10
6	Operation	operator: 24 operands: 11
7	Operation	operator: 14 operands: 12
8	Operation	operator: 14 operands: 13
9	Operation	operator: 14 operands: 15
10	Operation	operator: 16 operands: 17
11	ExprTuple	21, 18
12	ExprTuple	26, 19
13	ExprTuple	27, 19
14	Literal
15	ExprTuple	21, 19
16	Literal
17	ExprTuple	20, 21
18	Operation	operator: 22 operand: 26
19	Literal
20	Operation	operator: 24 operands: 25
21	Variable
22	Literal
23	ExprTuple	26
24	Literal
25	ExprTuple	26, 27
26	Variable
27	Variable