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Expression of type Lambda

from the theory of proveit.logic.sets.comprehension

In [1]:
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
from proveit.logic import And, InSet, NotEquals
from proveit.numbers import Integer, frac, zero
In [2]:
# build up the expression from sub-expressions
expr = Lambda([a, b], Conditional(frac(a, b), And(InSet(a, Integer), InSet(b, Integer), NotEquals(b, zero))))
expr:
In [3]:
# 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
In [4]:
# Show the LaTeX representation of the expression for convenience if you need it.
print(stored_expr.latex())
\left(a, b\right) \mapsto \left\{\frac{a}{b} \textrm{ if } a \in \mathbb{Z} ,  b \in \mathbb{Z} ,  b \neq 0\right..
In [5]:
stored_expr.style_options()
no style options
In [6]:
# display the expression information
stored_expr.expr_info()
 core typesub-expressionsexpression
0Lambdaparameters: 5
body: 1
1Conditionalvalue: 2
condition: 3
2Operationoperator: 4
operands: 5
3Operationoperator: 6
operands: 7
4Literal
5ExprTuple16, 18
6Literal
7ExprTuple8, 9, 10
8Operationoperator: 12
operands: 11
9Operationoperator: 12
operands: 13
10Operationoperator: 14
operands: 15
11ExprTuple16, 17
12Literal
13ExprTuple18, 17
14Literal
15ExprTuple18, 19
16Variable
17Literal
18Variable
19Literal