[GAP Forum] How to obtain the incidence matrix of a partial geometry?

[Felix Goldberg]

Hello all,

I am running the code in the example in Section 9.2 of the GRAPE manual (
http://www.maths.qmul.ac.uk/~leonard/grape/manual/CHAP009.htm) , which
generates the Haemers partial geometry pg(4,17,2).

All works well but I cannot understand where exactly the incidence matrix
is stored and how to access it. The manual (referred to above) says that
there is a *delta* associated to the geometry output by the function
PartialLinearSpaces
but I can't find it.

I tried to run RecNames on the output (the variable called *haemers*) and
got this:

[ "names", "group", "order", "representatives", "isSimple", "isGraph",
"schreierVector", "adjacencies" ]

No sign of *delta* and apparently no incidence matrix.

Any help will be greatly appreciated.

Thanks,
Felix




-- 
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Felix Goldberg, Ph. D.
www.technion.ac.il/~felixg <http://www.technion.ac.il/%7Efelixg>