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Expression of type Implies

from the theory of proveit.logic.equality

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, Function, Lambda, h, n, theta
from proveit.logic import Equals, Forall, Implies, InSet
from proveit.numbers import Natural
In [2]:
# build up the expression from sub-expressions
sub_expr1 = [n]
sub_expr2 = Function(h, sub_expr1)
sub_expr3 = Function(theta, sub_expr1)
sub_expr4 = InSet(n, Natural)
expr = Implies(Forall(instance_param_or_params = sub_expr1, instance_expr = Equals(sub_expr2, sub_expr3), domain = Natural), Equals(Lambda(n, Conditional(sub_expr2, sub_expr4)), Lambda(n, Conditional(sub_expr3, sub_expr4))).with_wrapping_at(2)).with_wrapping_at(2)
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())
\begin{array}{c} \begin{array}{l} \left[\forall_{n \in \mathbb{N}}~\left(h\left(n\right) = \theta\left(n\right)\right)\right] \Rightarrow  \\ \left(\begin{array}{c} \begin{array}{l} \left[n \mapsto \left\{h\left(n\right) \textrm{ if } n \in \mathbb{N}\right..\right] =  \\ \left[n \mapsto \left\{\theta\left(n\right) \textrm{ if } n \in \mathbb{N}\right..\right] \end{array} \end{array}\right) \end{array} \end{array}
In [5]:
stored_expr.style_options()
namedescriptiondefaultcurrent valuerelated methods
operation'infix' or 'function' style formattinginfixinfix
wrap_positionsposition(s) at which wrapping is to occur; '2 n - 1' is after the nth operand, '2 n' is after the nth operation.()(2)('with_wrapping_at', 'with_wrap_before_operator', 'with_wrap_after_operator', 'without_wrapping', 'wrap_positions')
justificationif any wrap positions are set, justify to the 'left', 'center', or 'right'centercenter('with_justification',)
directionDirection of the relation (normal or reversed)normalnormal('with_direction_reversed', 'is_reversed')
In [6]:
# display the expression information
stored_expr.expr_info()
 core typesub-expressionsexpression
0Operationoperator: 1
operands: 2
1Literal
2ExprTuple3, 4
3Operationoperator: 5
operand: 8
4Operationoperator: 16
operands: 7
5Literal
6ExprTuple8
7ExprTuple9, 10
8Lambdaparameter: 26
body: 11
9Lambdaparameter: 26
body: 12
10Lambdaparameter: 26
body: 13
11Conditionalvalue: 14
condition: 15
12Conditionalvalue: 20
condition: 15
13Conditionalvalue: 21
condition: 15
14Operationoperator: 16
operands: 17
15Operationoperator: 18
operands: 19
16Literal
17ExprTuple20, 21
18Literal
19ExprTuple26, 22
20Operationoperator: 23
operand: 26
21Operationoperator: 24
operand: 26
22Literal
23Variable
24Variable
25ExprTuple26
26Variable