OpenMath Content Dictionary: complex1

Canonical URL:
http://www.openmath.org/cd/complex1.ocd
CD Base:
http://www.openmath.org/cd
CD File:
complex1.ocd
CD as XML Encoded OpenMath:
complex1.omcd
Defines:
argument, complex_cartesian, complex_polar, conjugate, imaginary, real
Date:
2004-03-30
Version:
3 (Revision 1)
Review Date:
2006-03-30
Status:
official


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  Author: OpenMath Consortium
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This CD is intended to be `compatible' with the MathML view of operations on and constructors for complex numbers.


complex_cartesian

Role:
application
Description:

This symbol represents a constructor function for complex numbers specified as the Cartesian coordinates of the relevant point on the complex plane. It takes two arguments, the first is a number x to denote the real part and the second a number y to denote the imaginary part of the complex number x + i y. (Where i is the square root of -1.)

Commented Mathematical property (CMP):
for all x,y | complex_cartesian(x,y) = x + iy
Formal Mathematical property (FMP):
x , y . x + y i = x + i y
Signatures:
sts


[Next: real] [Last: conjugate] [Top]

real

Role:
application
Description:

This represents the real part of a complex number

Commented Mathematical property (CMP):
for all x,y | x = real(x+iy)
Formal Mathematical property (FMP):
x , y . x = real ( x + y i )
Signatures:
sts


[Next: imaginary] [Previous: complex_cartesian] [Top]

imaginary

Role:
application
Description:

This represents the imaginary part of a complex number

Commented Mathematical property (CMP):
for all x,y | y = imaginary(x+iy)
Formal Mathematical property (FMP):
x , y . y = imaginary ( x + y i )
Signatures:
sts


[Next: complex_polar] [Previous: real] [Top]

complex_polar

Role:
application
Description:

This symbol represents a constructor function for complex numbers specified as the polar coordinates of the relevant point on the complex plane. It takes two arguments, the first is a nonnegative number r to denote the magnitude and the second a number theta (given in radians) to denote the argument of the complex number r e^(i theta). (i and e are defined as in this CD).

Commented Mathematical property (CMP):
for all r,a | complex_polar(r,a) = r*e^(a*i)
Formal Mathematical property (FMP):
r , a . r e a i = r exp ( a i )
Commented Mathematical property (CMP):
for all x,y,r,a | (r sin a = y and r cos a = x) implies (complex_polar(r,a) = complex_cartesian(x,y)
Formal Mathematical property (FMP):
x , y , r , a . r sin ( a ) = y r cos ( a ) = x r e a i = x + y i
Commented Mathematical property (CMP):
for all x | if a is a real number and k is an integer then complex_polar(x,a) = complex_polar(x,a+2*pi*k)
Formal Mathematical property (FMP):
x . a R k Z x e a i = x e ( a + 2 π k ) i
Example:
i = complex_polar(1,pi/2)
i = e π 2 i
Signatures:
sts


[Next: argument] [Previous: imaginary] [Top]

argument

Role:
application
Description:

This symbol represents the unary function which returns the argument of a complex number, viz. the angle which a straight line drawn from the number to zero makes with the Real line (measured anti-clockwise). The argument to the symbol is the complex number whos argument is being taken.

Commented Mathematical property (CMP):
for all r,a | argument(complex_polar(r,a)=a)
Formal Mathematical property (FMP):
r , a . argument ( r e a i ) = a
Commented Mathematical property (CMP):
the argument of x+i*y = arctan(y/x) (if x is positive)
Formal Mathematical property (FMP):
x > 0 argument ( x + y i ) = arctan ( y x )
Commented Mathematical property (CMP):
the argument of x+i*y = arctan(y,x) (two-argument arctan from transc2)
Formal Mathematical property (FMP):
argument ( x + y i ) = arctan ( y , x )
Signatures:
sts


[Next: conjugate] [Previous: complex_polar] [Top]

conjugate

Role:
application
Description:

A unary operator representing the complex conjugate of its argument.

Commented Mathematical property (CMP):
if a is a complex number then (conjugate(a) + a) is a real number
Formal Mathematical property (FMP):
a C ( a ¯ + a ) R
Signatures:
sts


[First: complex_cartesian] [Previous: argument] [Top]