Moebius Function on the Lattice of Dense Subgraphs
نویسنده
چکیده
The l\[oebius fun ct ion Ik on the Ialti ce of k-de n ~e subg ra phs of a co nnccted graph, defin ed in a pre vious pa per, is calcu lated fo r graphs G containing isthmu scs and a rt icul ators. IJ evaluated for the null graph q, is shown to van ish if a contain s a n isthmus, whi Ie for a ny integer q there exist graphs containing a r t iculators for whi ch II (q,) = q. The " lattice of path sets" joining a p a ir of poin ts a nd t he latti ce of g raphs "associated wi t h a a nd a subgrap h a"' are defin ed and the :\foebius function s on these latt ices ,tre 8hOIl'n in ce rta in ca",cs to be reI ated to /J.
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