On The Binomial Edge Ideal of a Pair of Graphs
نویسندگان
چکیده
We characterize all pairs of graphs (G1, G2), for which the binomial edge ideal JG1,G2 has linear relations. We show that JG1,G2 has a linear resolution if and only if G1 and G2 are complete and one of them is just an edge. We also compute some of the graded Betti numbers of the binomial edge ideal of a pair of graphs with respect to some graphical terms. In particular, we show that for every pair of graphs (G1, G2) with girth (i.e. the length of a shortest cycle in the graph) greater than 3, βi,i+2(JG1,G2) = 0, for all i. Moreover, we give a lower bound for the Castelnuovo-Mumford regularity of any binomial edge ideal JG1,G2 and hence the ideal of adjacent 2-minors of a generic matrix. We also obtain an upper bound for the regularity of JG1,G2 , if G1 is complete and G2 is a closed graph.
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ورودعنوان ژورنال:
- Electr. J. Comb.
دوره 20 شماره
صفحات -
تاریخ انتشار 2013