# HG changeset patch
# User Nathann Cohen
# Date 1250442254 25200
# Node ID cdb5c193cb8772285b84bc4a3584ec3960d3f84c
# Parent 89c9f97b55c319ea421adfb46aaad7202e027037
Function Graph.ISR, with symbolics from numerical.MIP
diff -r 89c9f97b55c3 -r cdb5c193cb87 sage/graphs/graph.py
--- a/sage/graphs/graph.py Sat Dec 12 18:41:49 2009 +0100
+++ b/sage/graphs/graph.py Sun Aug 16 10:04:14 2009 -0700
@@ -10585,6 +10585,109 @@
else:
raise ValueError("The 'algorithm' keyword must be set to either 'DLX' or 'MILP'.")
+ def ISR(self,family):
+ r"""
+ Returns an independent set of representatives.
+
+ Given a graph `G` and and a family `F=\{F_i:i\in [1,...,k]\}` of subsets
+ of ``g.vertices()``, an ISR ( Independent Set of Reprersentatives ) is an
+ assignation of a vertex `v_i\in F_i` to each set `F_i` such that
+ `v_i != v_j` if `i