Dear Ralf,
I continued to work on the multisort species, but now I have the following
design problem:
a crucial step in producing the isomorphism types for the composition FoG is to
produce a multiset of isomorphismtypes of G, each structure having the same
cardinality. For example, suppose we are given labels {1,2} and {3,4}, and G
is the species of graphs. We have two isomorphismtypes, namely the graph with
one edge and the graph without edges. We now want to obtain three different
sets, each containing two structures: (omitting many braces)
1 3 1 3 1 3
| | , | ,
2 4 2 4 2 4
Allowing repeated labels this is straightforward: I produce the
isomorphismtypes of G[1,1], and then produce a multiset-composition of the
result. If all labels have to be distinct, I would have to relabel the
structures, i.e., I would do it as follows:
1 1
isomorphismTypes([1,2])$G returns | and
2 2
multiset composition thereof returns
1 1 1 1 1 1
| | , | ,
2 2 2 2 2 2
relabel the structures to obtain
1 3 1 3 1 3
| | , | ,
2 4 2 4 2 4
Do we really want to do this?
Martin
-------------------------------------------------------------------------
This SF.net email is sponsored by DB2 Express
Download DB2 Express C - the FREE version of DB2 express and take
control of your XML. No limits. Just data. Click to get it now.
http://sourceforge.net/powerbar/db2/
_______________________________________________
Aldor-combinat-devel mailing list
Aldor-combinat-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/aldor-combinat-devel
