Expression of type Lambda

from the theory of proveit.numbers.functions

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, ConditionalSet, Lambda, i, j
from proveit.logic import Equals, NotEquals
from proveit.numbers import KroneckerDelta, one, zero

# build up the expression from sub-expressions
expr = Lambda([i, j], Equals(KroneckerDelta(i, j), ConditionalSet(Conditional(one, Equals(i, j)), Conditional(zero, NotEquals(i, j)))))

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(i, j\right) \mapsto \left(\delta_{i, j} = \left\{\begin{array}{ccc}1 \textrm{ if } i = j \\ 0 \textrm{ if } i \neq j\end{array}\right..\right)

stored_expr.style_options()

no style options

# display the expression information
stored_expr.expr_info()

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