Expression of type Equals

from the theory of proveit.numbers.addition

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 ExprRange, Variable, a, b, n
from proveit.core_expr_types import Len, a_1_to_n
from proveit.logic import Equals
from proveit.numbers import Add, one, two

# build up the expression from sub-expressions
sub_expr1 = Variable("_a", latex_format = r"{_{-}a}")
expr = Equals(Len(operands = [a, b, a_1_to_n]), Len(operands = [ExprRange(sub_expr1, sub_expr1, one, Add(n, two))]))

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(a, b,a_{1}, a_{2}, \ldots, a_{n}\right)| = |\left(1, 2, \ldots, \left(n + 2\right)\right)|

stored_expr.style_options()

name	description	default	current value	related methods
operation	'infix' or 'function' style formatting	infix	infix
wrap_positions	position(s) at which wrapping is to occur; '2 n - 1' is after the nth operand, '2 n' is after the nth operation.	()	()	('with_wrapping_at', 'with_wrap_before_operator', 'with_wrap_after_operator', 'without_wrapping', 'wrap_positions')
justification	if any wrap positions are set, justify to the 'left', 'center', or 'right'	center	center	('with_justification',)
direction	Direction of the relation (normal or reversed)	normal	normal	('with_direction_reversed', 'is_reversed')

# display the expression information
stored_expr.expr_info()

	core type	sub-expressions	expression
0	Operation	operator: 1 operands: 2
1	Literal
2	ExprTuple	3, 4
3	Operation	operator: 6 operands: 5
4	Operation	operator: 6 operands: 7
5	ExprTuple	18, 8, 9
6	Literal
7	ExprTuple	10
8	Variable
9	ExprRange	lambda_map: 11 start_index: 13 end_index: 20
10	ExprRange	lambda_map: 12 start_index: 13 end_index: 14
11	Lambda	parameter: 22 body: 15
12	Lambda	parameter: 22 body: 22
13	Literal
14	Operation	operator: 16 operands: 17
15	IndexedVar	variable: 18 index: 22
16	Literal
17	ExprTuple	20, 21
18	Variable
19	ExprTuple	22
20	Variable
21	Literal
22	Variable