Expression of type Lambda

from the theory of proveit.logic.sets.functions.injections

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 A, Conditional, Lambda, a, b, fa, fb
from proveit.logic import And, InSet, NotEquals

# build up the expression from sub-expressions
expr = Lambda([a, b], Conditional(NotEquals(fa, fb), And(InSet(a, A), InSet(b, A), NotEquals(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())

\left(a, b\right) \mapsto \left\{f\left(a\right) \neq f\left(b\right) \textrm{ if } a \in A ,  b \in A ,  a \neq b\right..

stored_expr.style_options()

no style options

# display the expression information
stored_expr.expr_info()

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