# from the theory of proveit.numbers.numerals.decimals¶

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 ExprRange, Lambda, Variable, a, b, c
from proveit.core_expr_types import Len
from proveit.logic import Equals
from proveit.numbers import one, three

In [2]:
# build up the expression from sub-expressions
sub_expr1 = Variable("_a", latex_format = r"{_{-}a}")
sub_expr2 = [a, b, c]
expr = Lambda(sub_expr2, Equals(Len(operands = sub_expr2), Len(operands = [ExprRange(sub_expr1, sub_expr1, one, three)])))

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, b, c\right) \mapsto \left(|\left(a, b, c\right)| = |\left(1, 2, \ldots, 3\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: 6
body: 1
1Operationoperator: 2
operands: 3
2Literal
3ExprTuple4, 5
4Operationoperator: 7
operands: 6
5Operationoperator: 7
operands: 8
6ExprTuple9, 10, 11
7Literal
8ExprTuple12
9Variable
10Variable
11Variable
12ExprRangelambda_map: 13
start_index: 14
end_index: 15
13Lambdaparameter: 17
body: 17
14Literal
15Literal
16ExprTuple17
17Variable