Expression of type Lambda

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, Lambda, a, b, k
from proveit.core_expr_types import alpha_k
from proveit.logic import InSet
from proveit.numbers import Interval

# build up the expression from sub-expressions
expr = Lambda(k, Conditional(alpha_k, InSet(k, Interval(a, b))))

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())

k \mapsto \left\{\alpha_{k} \textrm{ if } k \in \{a~\ldotp \ldotp~b\}\right..

stored_expr.style_options()

no style options

# display the expression information
stored_expr.expr_info()

	core type	sub-expressions	expression
0	Lambda	parameter: 8 body: 1
1	Conditional	value: 2 condition: 3
2	IndexedVar	variable: 4 index: 8
3	Operation	operator: 6 operands: 7
4	Variable
5	ExprTuple	8
6	Literal
7	ExprTuple	8, 9
8	Variable
9	Operation	operator: 10 operands: 11
10	Literal
11	ExprTuple	12, 13
12	Variable
13	Variable