Re: Sign Definiteness

swagat wrote:

> Dear All,
>
> IF two matrices are P.D (positive definite), is their sum also P.D?
>
> How can test this in MuPAD?
>
>

I needed 5 seconds to solve this in my head (think about determinants of 2x2
- matrices).
The MuPAD syntax would be
assume(Type::Real):
is((a1*d1 - b1*c1 > 0 and a2*d2 - b2*c2 > 0) ==> (a1+a2)*(d1+d2)
-(b1+b2)*(c1+c2) > 0)

I am glad to announce you that this is UNKNOWN such that you will have to
spend those 5 seconds yourself.

--
Stefan Wehmeier
stefanw@xxxxxxxxxxxxxxxxxxxxx
.

Relevant Pages

  • Sign Definiteness
    ... How can test this in MuPAD? ... Regards, ... Swagat ... Prev by Date: ...
    (sci.math.symbolic)
  • Assumptions in MuPAD
    ... statement in MuPAD. ... Thanks and Regards, ... Prev by Date: ...
    (sci.math.symbolic)
  • Checking conditions in MuPAD
    ... I am new to this group and also new to "MuPAD". ... like to thank MuPAD group for making this software freely available. ... Swagat ... Prev by Date: ...
    (sci.math.symbolic)
  • Re: Sign Definiteness
    ... >IF two matrices are P.D, is their sum also P.D? ... Why would you use MuPad to check that v'v> 0 for nonzero v, ... Prev by Date: ...
    (sci.math.symbolic)
  • Re: Simplifying radicals
    ... It seems MuPAD should learn combining cot terms. ... Christopher ... Prev by Date: ...
    (sci.math.symbolic)