Hi,

how can I generate, in a fast enough way, connected graphs for which the 
clique complex is pure, ie, for which all containmentwise maximal cliques 
are of the same size ?

Fast enough here means that I can produce examples of such graphs with 20 
vertices,  edge degrees between 10 and 14 (an example of such a graph on 
diagonals in a regular 7-gon with edges being pairwise noncrossing 
diagonals and the resulting clique complex the dual associahedron of 
dimension 4).

What I got so far is:

from sage.graphs.independent_sets import IndependentSets
for G in graphs.nauty_geng("20 -c -d10 -D14"):
    cliques = IndependentSets(G, maximal = True, complement = True)
    sizes = map(len,cliques)
    size_min = min(sizes)
    if size_min > 4:
        size_max = max(sizes)
        if size_min == size_max:
            print list(cliques)

But this seems to be too slow, already because it takes too long for this 
to turn the graph6 string from nauty into a sage graph.

Does someone know how I can do this computation more low-level? Best would 
clearly be to teach nauty to only iter through such graphs, but that does 
not seem to be possible...

Thanks, Christian

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