conjugates in SR disappear

Håkan Granath

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Dec 30, 2009, 1:56:42 PM12/30/09

to sage-devel

When using conjugate() in the symbolic ring some functions seem to
forget the conjugate:

----------------------------------------------------------------------
| Sage Version 4.3, Release Date: 2009-12-24 |
| Type notebook() for the GUI, and license() for information. |
----------------------------------------------------------------------
sage: var('z')
z
sage: m=z*z.conjugate()
sage: m
z*conjugate(z)
sage: m.factor()
z^2
sage: m.simplify()
z^2

/Håkan

Burcin Erocal

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Dec 30, 2009, 2:42:53 PM12/30/09

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The factor() and simplify() functions call maxima, which by default
assumes the variables are real. This is already in trac as #6862:

http://trac.sagemath.org/sage_trac/ticket/6862

The first comment on the ticket by Karl-Dieter shows a workaround:

sage: var('z')
z

sage: assume(z, 'complex')
sage: t = z*conjugate(z); t
z*conjugate(z)
sage: t.factor()
z*conjugate(z)
sage: t.simplify()
z*conjugate(z)

Happy new year!

Cheers,
Burcin

Håkan Granath

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Dec 30, 2009, 2:54:12 PM12/30/09

to sage-devel

> The first comment on the ticket by Karl-Dieter shows a workaround:

Thank you!

/Håkan

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