From: Lily Selivan on
Hello. I have a question on linear algebra.

Is the product of diagonal elements of a square matrix the invariant? If it is true how to prove this?

Thank you very much!
From: Ken Pledger on
In article
<100899668.29383.1277919887096.JavaMail.root(a)gallium.mathforum.org>,
Lily Selivan <selivan0804(a)gmail.com> wrote:

> ....
> Is the product of diagonal elements of a square matrix the invariant? If it
> is true how to prove this? ....


Try some simple 2 x 2 examples. I think you'll pretty soon find
that it's false.

Ken Pledger.
From: Gerry Myerson on
In article
<ken.pledger-B972B1.08410201072010(a)62-183-169-81.bb.dnainternet.fi>,
Ken Pledger <ken.pledger(a)mcs.vuw.ac.nz> wrote:

> In article
> <100899668.29383.1277919887096.JavaMail.root(a)gallium.mathforum.org>,
> Lily Selivan <selivan0804(a)gmail.com> wrote:
>
> > ....
> > Is the product of diagonal elements of a square matrix the invariant? If it
> > is true how to prove this? ....
>
>
> Try some simple 2 x 2 examples. I think you'll pretty soon find
> that it's false.

She won't find it true or false if she doesn't know what "invariant"
means in this context, and I suspect that's the case, else, why ask
the question?

So, let's tell her; in this context, we say George is an invariant if
the George value of A equals the George value of B-inverse A B
for all A and all invertible B.

--
Gerry Myerson (gerry(a)maths.mq.edi.ai) (i -> u for email)