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Expression of type Lambda

from the theory of proveit.trigonometry

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, Lambda, a, b, r
from proveit.logic import And, Equals, InSet
from proveit.numbers import Abs, Exp, Mult, Real, e, frac, i, subtract, two
from proveit.trigonometry import Sin
In [2]:
# build up the expression from sub-expressions
expr = Lambda([a, b], Conditional(Equals(Abs(subtract(Mult(r, Exp(e, Mult(i, a))), Mult(r, Exp(e, Mult(i, b))))), Mult(two, r, Sin(frac(Abs(subtract(a, b)), two)))), And(InSet(a, Real), InSet(b, Real))))
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\right) \mapsto \left\{\left|\left(r \cdot \mathsf{e}^{\mathsf{i} \cdot a}\right) - \left(r \cdot \mathsf{e}^{\mathsf{i} \cdot b}\right)\right| = \left(2 \cdot r \cdot \sin{\frac{\left|a - b\right|}{2}}\right) \textrm{ if } a \in \mathbb{R} ,  b \in \mathbb{R}\right..
In [5]:
stored_expr.style_options()
no style options
In [6]:
# display the expression information
stored_expr.expr_info()
 core typesub-expressionsexpression
0Lambdaparameters: 1
body: 2
1ExprTuple50, 57
2Conditionalvalue: 3
condition: 4
3Operationoperator: 5
operands: 6
4Operationoperator: 7
operands: 8
5Literal
6ExprTuple9, 10
7Literal
8ExprTuple11, 12
9Operationoperator: 37
operand: 18
10Operationoperator: 52
operands: 14
11Operationoperator: 16
operands: 15
12Operationoperator: 16
operands: 17
13ExprTuple18
14ExprTuple34, 40, 19
15ExprTuple50, 20
16Literal
17ExprTuple57, 20
18Operationoperator: 46
operands: 21
19Operationoperator: 22
operand: 26
20Literal
21ExprTuple24, 25
22Literal
23ExprTuple26
24Operationoperator: 52
operands: 27
25Operationoperator: 54
operand: 32
26Operationoperator: 29
operands: 30
27ExprTuple40, 31
28ExprTuple32
29Literal
30ExprTuple33, 34
31Operationoperator: 44
operands: 35
32Operationoperator: 52
operands: 36
33Operationoperator: 37
operand: 42
34Literal
35ExprTuple48, 39
36ExprTuple40, 41
37Literal
38ExprTuple42
39Operationoperator: 52
operands: 43
40Variable
41Operationoperator: 44
operands: 45
42Operationoperator: 46
operands: 47
43ExprTuple56, 50
44Literal
45ExprTuple48, 49
46Literal
47ExprTuple50, 51
48Literal
49Operationoperator: 52
operands: 53
50Variable
51Operationoperator: 54
operand: 57
52Literal
53ExprTuple56, 57
54Literal
55ExprTuple57
56Literal
57Variable