Wikipedia:Articles for deletion/Quaternionic matrix: Difference between revisions

Revision as of 21:05, 1 September 2010

Revision as of 22:48, 1 September 2010

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** I don't understand where did you get the impression that the article is only on 2x2 matrices. --[[User:Cyclopia|<font color="green">Cycl</font><big>o</big><font color="green">pia</font>]][[User talk:Cyclopia|<font color="red">^talk</font>]] 19:41, 1 September 2010 (UTC)

***The definition ("matrix of quaternions") applies in any dimension and the first product given trivially generalises but the second doesn't, it only works as described in 2D. So in higher dimensions its not clear if this product is defined or if there are other maybe multiple products which simplify to this in 2D.--<small>[[User:JohnBlackburne|JohnBlackburne]]</small>^{[[User_talk:JohnBlackburne|words]]}<sub style="margin-left:-2.0ex;">[[Special:Contributions/JohnBlackburne|deeds]]</sub> 21:05, 1 September 2010 (UTC)

****Oh ok, I thought you referred to it being 2x2, not being bidimensional. --[[User:Cyclopia|<font color="green">Cycl</font><big>o</big><font color="green">pia</font>]][[User talk:Cyclopia|<font color="red">^talk</font>]] 22:48, 1 September 2010 (UTC)

** The definition is a bit of a tautology, and the sources were probably assuming readers would fill in the gaps. I'm thinking [http://books.google.com/books?id=Un_15Im3NhUC&pg=PA31#v=onepage&f=false] probably covers the subject enough to establish notability. The article doesn't list any sources though, and it's unclear to me how much of the material should be removed. The definition alone isn't enough to justify the existence of the article.--[[User:RDBury|RDBury]] ([[User talk:RDBury|talk]]) 20:16, 31 August 2010 (UTC)

*** There is definitely material that can bring the article beyond a mere definition: e.g. here it is an article [http://books.google.com/books?hl=en&lr=&id=HuSqsKIzTSYC&oi=fnd&pg=PA19&dq=%22quaternionic+matrix%22&ots=lYRkWSoKRR&sig=rTC7e_rXQpq1tgSjinS1dhHGAbE#v=onepage&q=%22quaternionic%20matrix%22&f=false on eigenvalues of a quaternionic matrix]. I am unfortunately far from having the mathematical competence to properly do that, I'm going to notify the appropriate Wikiproject. --[[User:Cyclopia|<font color="green">Cycl</font><big>o</big><font color="green">pia</font>]][[User talk:Cyclopia|<font color="red">^talk</font>]] 19:40, 1 September 2010 (UTC)

* '''comment''' The determinant and therefore the eignenvalue problem are where you're going to have problems with such matrices. When calculating the determinant of a real or complex matrix you can do so in a variety of ways with order of multiplication usually ignored, but order matters when multiplying quaternions. A lot of the sources seem to be concerned with this problem, but more as something they're all trying to address, perhaps in different ways, rather than a known definition they can all agree on so which we can be pretty sure of.--<small>[[User:JohnBlackburne|JohnBlackburne]]</small>^{[[User_talk:JohnBlackburne|words]]}<sub style="margin-left:-2.0ex;">[[Special:Contributions/JohnBlackburne|deeds]]</sub> 21:05, 1 September 2010 (UTC)

** Which is, if anything, a reason more to keep this article, not to delete it. It seems a lively topic in mathematics. --[[User:Cyclopia|<font color="green">Cycl</font><big>o</big><font color="green">pia</font>]][[User talk:Cyclopia|<font color="red">^talk</font>]] 22:48, 1 September 2010 (UTC)