logo

Expression of type Lambda

from the theory of proveit.core_expr_types.conditionals

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, Q, a, b
from proveit.logic import Equals, Implies
In [2]:
# build up the expression from sub-expressions
expr = Lambda([a, b, Q], Conditional(Equals(Conditional(a, Q), Conditional(b, Q)).with_wrapping_at(1), Implies(Q, Equals(a, b))))
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, Q\right) \mapsto \left\{\begin{array}{c} \begin{array}{l} \left\{a \textrm{ if } Q\right.. \\  = \left\{b \textrm{ if } Q\right.. \end{array} \end{array} \textrm{ if } Q \Rightarrow \left(a = b\right)\right..
In [5]:
stored_expr.style_options()
no style options
In [6]:
# display the expression information
stored_expr.expr_info()
 core typesub-expressionsexpression
0Lambdaparameters: 1
body: 2
1ExprTuple14, 15, 11
2Conditionalvalue: 3
condition: 4
3Operationoperator: 12
operands: 5
4Operationoperator: 6
operands: 7
5ExprTuple8, 9
6Literal
7ExprTuple11, 10
8Conditionalvalue: 14
condition: 11
9Conditionalvalue: 15
condition: 11
10Operationoperator: 12
operands: 13
11Variable
12Literal
13ExprTuple14, 15
14Variable
15Variable