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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 Mult, 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)), Mult(ExprRange(sub_expr1, Norm(sub_expr2), one, i))), And(ExprRange(sub_expr1, InSet(sub_expr2, IndexedVar(V, sub_expr1)), 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 \| = \left(\left \|a_{1}\right \| \cdot  \left \|a_{2}\right \| \cdot  \ldots \cdot  \left \|a_{i}\right \|\right) \textrm{ if } \left(a_{1} \in V_{1}\right) \land  \left(a_{2} \in V_{2}\right) \land  \ldots \land  \left(a_{i} \in V_{i}\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: 19
body: 1
1Conditionalvalue: 2
condition: 3
2Operationoperator: 4
operands: 5
3Operationoperator: 6
operands: 7
4Literal
5ExprTuple8, 9
6Literal
7ExprTuple10
8Operationoperator: 29
operand: 15
9Operationoperator: 12
operands: 13
10ExprRangelambda_map: 14
start_index: 27
end_index: 28
11ExprTuple15
12Literal
13ExprTuple16
14Lambdaparameter: 35
body: 17
15Operationoperator: 18
operands: 19
16ExprRangelambda_map: 20
start_index: 27
end_index: 28
17Operationoperator: 21
operands: 22
18Literal
19ExprTuple23
20Lambdaparameter: 35
body: 24
21Literal
22ExprTuple32, 25
23ExprRangelambda_map: 26
start_index: 27
end_index: 28
24Operationoperator: 29
operand: 32
25IndexedVarvariable: 31
index: 35
26Lambdaparameter: 35
body: 32
27Literal
28Variable
29Literal
30ExprTuple32
31Variable
32IndexedVarvariable: 33
index: 35
33Variable
34ExprTuple35
35Variable