Expression of type Conditional

from the theory of proveit.core_expr_types.tuples

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, ExprRange, Variable, n, x
from proveit.logic import Equals, InSet
from proveit.numbers import NaturalPos, one, subtract

# build up the expression from sub-expressions
sub_expr1 = Variable("_a", latex_format = r"{_{-}a}")
expr = Conditional(Equals([ExprRange(sub_expr1, x, one, n)], [x, ExprRange(sub_expr1, x, one, subtract(n, one))]), InSet(n, NaturalPos))

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(x, x, ..\left(n - 3\right) \times.., x\right) = \left(x,x, x, ..\left(n - 4\right) \times.., x\right) \textrm{ if } n \in \mathbb{N}^+\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 operands: 4
2	Operation	operator: 5 operands: 6
3	Literal
4	ExprTuple	7, 8
5	Literal
6	ExprTuple	19, 9
7	ExprTuple	10
8	ExprTuple	15, 11
9	Literal
10	ExprRange	lambda_map: 12 start_index: 23 end_index: 19
11	ExprRange	lambda_map: 12 start_index: 23 end_index: 13
12	Lambda	parameter: 18 body: 15
13	Operation	operator: 16 operands: 17
14	ExprTuple	18
15	Variable
16	Literal
17	ExprTuple	19, 20
18	Variable
19	Variable
20	Operation	operator: 21 operand: 23
21	Literal
22	ExprTuple	23
23	Literal