In this paper we provide some exact formulas for projective dimension and the regularity of powers of edge ideals of vertex-weighted rooted forests. These formulas are functions of the weight of the vertices and the number of edges. We also give some examples to show that these formulas are related to direction selection and the assumptions about rooted forest such that $w(x)geq 2$ if $d(x) eq 1$ cannot be dropped.
In this paper we provide some exact formulas for the projective dimension and the regularity of edge ideals associated to three special types of vertex-weighted oriented $m$-partite graphs. These formulas are functions of the weight and number of ver
tices. We also give some examples to show that these formulas are related to direction selection and the weight of vertices.
In this article, we prove that for several classes of graphs, the Castelnuovo-Mumford regularity of symbolic powers of their edge ideals coincide with that of their ordinary powers.
In this paper we provide some precise formulas for regularity of powers of edge ideal of the disjoint union of some weighted oriented gap-free bipartite graphs. For the projective dimension of such an edge ideal, we give its exact formula. Meanwhile,
we also give the upper and lower bounds of projective dimension of higher power of such edge ideals. Some examples show that these formulas are related to direction selection.
In this article, we study the regularity of integral closure of powers of edge ideals. We obtain a lower bound for the regularity of integral closure of powers of edge ideals in terms of induced matching number of graphs. We prove that the regularity
of integral closure of powers of edge ideals of graphs with at most two odd cycles is the same as the regularity of their powers.
Let $mathcal{D}$ be a weighted oriented graph and $I(mathcal{D})$ be its edge ideal. In this paper, we show that all the symbolic and ordinary powers of $I(mathcal{D})$ coincide when $mathcal{D}$ is a weighted oriented certain class of tree. Fi
nally, we give necessary and sufficient conditions for the equality of ordinary and symbolic powers of naturally oriented lines.
Li Xu
,Guangjun Zhu
,Hong Wang
.
(2019)
.
"Projective dimension and regularity of powers of edge ideals of vertex-weighted rooted forests"
.
Guangjun Zhu
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