logo

Expression of type Conditional

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, ExprRange, IndexedVar, Variable, n, x
from proveit.core_expr_types import x_1_to_np1
from proveit.logic import Equals, Forall, InSet
from proveit.numbers import Add, NaturalPos, one
In [2]:
# build up the expression from sub-expressions
sub_expr1 = Variable("_a", latex_format = r"{_{-}a}")
expr = Conditional(Forall(instance_param_or_params = [x_1_to_np1], instance_expr = Equals(IndexedVar(x, one), IndexedVar(x, Add(n, one))), condition = ExprRange(sub_expr1, Equals(IndexedVar(x, sub_expr1), IndexedVar(x, Add(sub_expr1, one))), one, n)), InSet(n, NaturalPos))
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\{\forall_{x_{1}, x_{2}, \ldots, x_{n + 1}~|~\left(x_{1} = x_{1 + 1}\right), \left(x_{2} = x_{2 + 1}\right), \ldots, \left(x_{n} = x_{n + 1}\right)}~\left(x_{1} = x_{n + 1}\right) \textrm{ if } n \in \mathbb{N}^+\right..
In [5]:
stored_expr.style_options()
namedescriptiondefaultcurrent valuerelated methods
condition_delimiter'comma' or 'and'commacomma('with_comma_delimiter', 'with_conjunction_delimiter')
In [6]:
# display the expression information
stored_expr.expr_info()
 core typesub-expressionsexpression
0Conditionalvalue: 1
condition: 2
1Operationoperator: 3
operand: 7
2Operationoperator: 5
operands: 6
3Literal
4ExprTuple7
5Literal
6ExprTuple29, 8
7Lambdaparameters: 9
body: 10
8Literal
9ExprTuple11
10Conditionalvalue: 12
condition: 13
11ExprRangelambda_map: 14
start_index: 39
end_index: 24
12Operationoperator: 27
operands: 15
13Operationoperator: 16
operands: 17
14Lambdaparameter: 38
body: 30
15ExprTuple18, 19
16Literal
17ExprTuple20
18IndexedVarvariable: 33
index: 39
19IndexedVarvariable: 33
index: 24
20ExprRangelambda_map: 23
start_index: 39
end_index: 29
21ExprTuple39
22ExprTuple24
23Lambdaparameter: 38
body: 25
24Operationoperator: 36
operands: 26
25Operationoperator: 27
operands: 28
26ExprTuple29, 39
27Literal
28ExprTuple30, 31
29Variable
30IndexedVarvariable: 33
index: 38
31IndexedVarvariable: 33
index: 35
32ExprTuple38
33Variable
34ExprTuple35
35Operationoperator: 36
operands: 37
36Literal
37ExprTuple38, 39
38Variable
39Literal