Expression of type Lambda

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, Lambda, 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 = Lambda([n, x], 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(n, x\right) \mapsto \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()

no style options

# display the expression information
stored_expr.expr_info()

	core type	sub-expressions	expression
0	Lambda	parameters: 1 body: 2
1	ExprTuple	21, 17
2	Conditional	value: 3 condition: 4
3	Operation	operator: 5 operands: 6
4	Operation	operator: 7 operands: 8
5	Literal
6	ExprTuple	9, 10
7	Literal
8	ExprTuple	21, 11
9	ExprTuple	12
10	ExprTuple	17, 13
11	Literal
12	ExprRange	lambda_map: 14 start_index: 25 end_index: 21
13	ExprRange	lambda_map: 14 start_index: 25 end_index: 15
14	Lambda	parameter: 20 body: 17
15	Operation	operator: 18 operands: 19
16	ExprTuple	20
17	Variable
18	Literal
19	ExprTuple	21, 22
20	Variable
21	Variable
22	Operation	operator: 23 operand: 25
23	Literal
24	ExprTuple	25
25	Literal