Read-only forum archive

vector spaces and relations

vector spaces and relations

nieto · Thu Oct 01, 2009 7:47 pm

Perhaps it is well known for you but I do not seem to find a useful command
that allows me to define a finite dimensional vector space with a polinomial constraint to be able to compute its dimension ( the first try would be to define it as a kernel). My problem is to define a
subvector space of the vector space of polynomials of degree 10 with a condition of multiplicty on these polinomials, namely that the up to the third order partial derivatives of each of these polynomials vanishes. I want to compute the dimension of this subvector space.
I have been browsing the libraries and have not found it directly but seem to find
some libraries useful but when I want to look at them closely; it seems they contain the authors´name but not the specific singular algorithm I need. How do I have direct access to these libraries, to look at specific singular commands?

Re: vector spaces and relations

malex · Fri Oct 02, 2009 12:37 am

Dear nieto,

please take a look at "central.lib":
http://www.singular.uni-kl.de/Manual/la ... htm#SEC499.
1. use PBW_eqDeg( 10 ); in order to get your enveloping vector space (may require a lot of memory).
2. use diff() instead of applyAdF in order to get your system of equations.
3. use linearMapKernel/linearCombinations to solve the sysystem.
Iterate steps 2/3 as in centerVS...

hope that helps,
Oleksandr

ps: Singular libraries (*.lib) are just plane text files so
that one could read the code with any text viewer.
(please try another editor and provide more details if that will not help)