Castelnuovo-Mumford regularity and any extended degree function can be thought of as complexity measures for the structure of finitely generated graded modules. A recent result of Doering, Gunston, Vasconcelos shows that both can be compared in case of a graded algebra. We extend this result to modules and analyze when the estimate is in fact an equality. A complete classification is obtained i...

*Correspondence: [email protected] 2Otto-von-Guericke Universität, Magdeburg, Germany Full list of author information is available at the end of the article Abstract We describe an algorithm which finds binomials in a given ideal I ⊂ Q[x1, . . . , xn] and in particular decides whether binomials exist in I at all. Binomials in polynomial ideals can be well hidden. For example, the lowest degr...

Recall that the (Mumford-Castelnuovo) regularity of M is the least integer ρ such that for each i all free generators of Fi lie in degree ≤ i + ρ, that is βi,j = 0, for j > i + ρ. In terms of Macaulay [Mac] regularity is the number of rows in the diagram produced by the “betti” command. A Betti number βi,j 6= 0 will be called extremal if βl,r = 0 for all l ≥ i and r ≥ j + 1, that is if βi,j is ...

In this note we generalize and unify two results on connectivity of graphs: one by Balinsky and Barnette, one by Athanasiadis. This is done through a simple proof using commutative algebra tools. In particular we use bounds for the Castelnuovo–Mumford regularity of their Stanley–Reisner rings. As a result, if ∆ is a simplicial d-pseudomanifold and s is the largest integer such that ∆ has a miss...

We give degree formulas for Grothendieck polynomials indexed by vexillary permutations and 1432-avoiding via tableau combinatorics. These generalize a formula degrees of symmetric which appeared in previous joint work the authors with Y. Ren A. St. Dizier. apply our to compute Castelnuovo-Mumford regularity classes generalized determinantal ideals. In particular, we combinatorial regularities a...