# from the theory of proveit.numbers.negation¶

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, ExprTuple, Lambda, x
from proveit.logic import Equals, InSet
from proveit.numbers import Complex, Mult, Neg, one

In [2]:
# build up the expression from sub-expressions
expr = ExprTuple(Lambda(x, Conditional(Equals(Mult(Neg(one), x), Neg(x)), InSet(x, Complex))))

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(x \mapsto \left\{\left(\left(-1\right) \cdot x\right) = \left(-x\right) \textrm{ if } x \in \mathbb{C}\right..\right)

In [5]:
stored_expr.style_options()

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

core typesub-expressionsexpression
0ExprTuple1
1Lambdaparameter: 16
body: 2
2Conditionalvalue: 3
condition: 4
3Operationoperator: 5
operands: 6
4Operationoperator: 7
operands: 8
5Literal
6ExprTuple9, 10
7Literal
8ExprTuple16, 11
9Operationoperator: 12
operands: 13
10Operationoperator: 17
operand: 16
11Literal
12Literal
13ExprTuple15, 16
14ExprTuple16
15Operationoperator: 17
operand: 19
16Variable
17Literal
18ExprTuple19
19Literal