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Expression of type Lambda

from the theory of proveit.linear_algebra.tensors

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, Lambda, V, Variable, a, i
from proveit.core_expr_types import a_1_to_i
from proveit.linear_algebra import Norm, TensorProd
from proveit.logic import And, Equals, InSet
from proveit.numbers import one
In [2]:
# build up the expression from sub-expressions
sub_expr1 = Variable("_a", latex_format = r"{_{-}a}")
sub_expr2 = IndexedVar(a, sub_expr1)
expr = Lambda([a_1_to_i], Conditional(Equals(Norm(TensorProd(a_1_to_i)), one), And(ExprRange(sub_expr1, InSet(sub_expr2, IndexedVar(V, sub_expr1)), one, i), And(ExprRange(sub_expr1, Equals(Norm(sub_expr2), one), one, i)))))
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_{1}, a_{2}, \ldots, a_{i}\right) \mapsto \left\{\left \|a_{1} {\otimes}  a_{2} {\otimes}  \ldots {\otimes}  a_{i}\right \| = 1 \textrm{ if } \left(a_{1} \in V_{1}\right) ,  \left(a_{2} \in V_{2}\right) ,  \ldots ,  \left(a_{i} \in V_{i}\right) ,  \left(\left \|a_{1}\right \| = 1\right) \land  \left(\left \|a_{2}\right \| = 1\right) \land  \ldots \land  \left(\left \|a_{i}\right \| = 1\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: 17
body: 1
1Conditionalvalue: 2
condition: 3
2Operationoperator: 27
operands: 4
3Operationoperator: 11
operands: 5
4ExprTuple6, 30
5ExprTuple7, 8
6Operationoperator: 31
operand: 13
7ExprRangelambda_map: 10
start_index: 30
end_index: 25
8Operationoperator: 11
operands: 12
9ExprTuple13
10Lambdaparameter: 36
body: 14
11Literal
12ExprTuple15
13Operationoperator: 16
operands: 17
14Operationoperator: 18
operands: 19
15ExprRangelambda_map: 20
start_index: 30
end_index: 25
16Literal
17ExprTuple21
18Literal
19ExprTuple33, 22
20Lambdaparameter: 36
body: 23
21ExprRangelambda_map: 24
start_index: 30
end_index: 25
22IndexedVarvariable: 26
index: 36
23Operationoperator: 27
operands: 28
24Lambdaparameter: 36
body: 33
25Variable
26Variable
27Literal
28ExprTuple29, 30
29Operationoperator: 31
operand: 33
30Literal
31Literal
32ExprTuple33
33IndexedVarvariable: 34
index: 36
34Variable
35ExprTuple36
36Variable