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, c, d, fj, gj, j
from proveit.logic import InSet
from proveit.numbers import Interval, Mult

# build up the expression from sub-expressions
expr = Lambda(j, Conditional(Mult(gj, fj), InSet(j, Interval(c, d))))

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())

j \mapsto \left\{g\left(j\right) \cdot f\left(j\right) \textrm{ if } j \in \{c~\ldotp \ldotp~d\}\right..

stored_expr.style_options()

no style options

# display the expression information
stored_expr.expr_info()

	core type	sub-expressions	expression
0	Lambda	parameter: 16 body: 1
1	Conditional	value: 2 condition: 3
2	Operation	operator: 4 operands: 5
3	Operation	operator: 6 operands: 7
4	Literal
5	ExprTuple	8, 9
6	Literal
7	ExprTuple	16, 10
8	Operation	operator: 11 operand: 16
9	Operation	operator: 12 operand: 16
10	Operation	operator: 14 operands: 15
11	Variable
12	Variable
13	ExprTuple	16
14	Literal
15	ExprTuple	17, 18
16	Variable
17	Variable
18	Variable