# from the theory of proveit.linear_algebra.addition¶

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.
# import Expression classes needed to build the expression
from proveit import Conditional, Lambda, a, i, va, vi
from proveit.linear_algebra import VecSum
from proveit.logic import Equals, InSet
from proveit.numbers import Integer, Interval

In [2]:
# build up the expression from sub-expressions
expr = Lambda(a, Conditional(Equals(VecSum(index_or_indices = [i], summand = vi, domain = Interval(a, a)), va), InSet(a, Integer)))

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())

a \mapsto \left\{\left(\sum_{i=a}^{a} v\left(i\right)\right) = v\left(a\right) \textrm{ if } a \in \mathbb{Z}\right..

In [5]:
stored_expr.style_options()

no style options
In [6]:
# display the expression information
stored_expr.expr_info()

core typesub-expressionsexpression
0Lambdaparameter: 25
body: 1
1Conditionalvalue: 2
condition: 3
2Operationoperator: 4
operands: 5
3Operationoperator: 19
operands: 6
4Literal
5ExprTuple7, 8
6ExprTuple25, 9
7Operationoperator: 10
operand: 13
8Operationoperator: 17
operand: 25
9Literal
10Literal
11ExprTuple13
12ExprTuple25
13Lambdaparameter: 21
body: 14
14Conditionalvalue: 15
condition: 16
15Operationoperator: 17
operand: 21
16Operationoperator: 19
operands: 20
17Variable
18ExprTuple21
19Literal
20ExprTuple21, 22
21Variable
22Operationoperator: 23
operands: 24
23Literal
24ExprTuple25, 25
25Variable