#16843: Zeromorphism
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Reporter: mkamalakshya | Owner: mkamalakshya
Type: defect | Status: needs_info
Priority: minor | Milestone: sage-6.4
Component: algebra | Resolution:
Keywords: days60 | Merged in:
Authors: Kamalakshya Mahatab | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Changes (by mkamalakshya):
* status: needs_work => needs_info
Old description:
> Gives error even though zero morphism is valid.
> {{{
> sage: H= Hom(QQ, QQ)
> sage: f=H(0)
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> File "_sage_input_4.py", line 10, in <module>
> exec compile(u'open("___code___.py","w").write("# -*- coding: utf-8
> -*-\\n" +
> _support_.preparse_worksheet_cell(base64.b64decode("Zj1IKDAp"),globals())+"\\n");
> execfile(os.path.abspath("___code___.py"))
> File "", line 1, in <module>
>
> File "/tmp/tmplncYUJ/___code___.py", line 3, in <module>
> exec compile(u'f=H(_sage_const_0 )
> File "", line 1, in <module>
>
> File "/home/kamalakshya/sage/local/lib/python2.7/site-
> packages/sage/rings/homset.py", line 184, in __call__
> raise TypeError("images do not define a valid homomorphism")
> TypeError: images do not define a valid homomorphism
> }}}
New description:
Should Zero morphism be a morphism of rings?
{{{
sage: H= Hom(QQ, QQ)
sage: f=H(0)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "_sage_input_4.py", line 10, in <module>
exec compile(u'open("___code___.py","w").write("# -*- coding: utf-8
-*-\\n" +
_support_.preparse_worksheet_cell(base64.b64decode("Zj1IKDAp"),globals())+"\\n");
execfile(os.path.abspath("___code___.py"))
File "", line 1, in <module>
File "/tmp/tmplncYUJ/___code___.py", line 3, in <module>
exec compile(u'f=H(_sage_const_0 )
File "", line 1, in <module>
File "/home/kamalakshya/sage/local/lib/python2.7/site-
packages/sage/rings/homset.py", line 184, in __call__
raise TypeError("images do not define a valid homomorphism")
TypeError: images do not define a valid homomorphism
}}}
In other words, do we assume that our homomorphisms take 1 to 1?
--
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Ticket URL: <http://trac.sagemath.org/ticket/16843#comment:5>
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