ABSTRACT: We consider the Hilbert function of the fiber cone of a graded filtration, and discuss good and bad properties of this function, especially for divisorial filtrations. We mention some open problems.
ABSTRACT: I will define the notion of Principal matrix from the critical binomials and survey some known results and some questions.
ABSTRACT: This talk is mainly based on a recent joint work with L. X. Dung and J. Elias: "Upper bounds on two Hilbert coefficients, Journal of Algebra,
633 (2023), 563 - 590". Some new upper bounds on the first and the second Hilbert coefficients of a Cohen-Macaulay module over a local ring are presented. Characterizations are provided for some upper bounds to be attained. The characterizations are given in terms of Hilbert series as well as in terms of the Castelnuovo-Mumford regularity of the associated graded module.
ABSTRACT: A very classical problem in algebraic geometry and commutative algebra is whether an algebraic curve in n space can be written set theoretically as the intersection of n-1 hypersurfaces. I will explain this problem and describe several approaches. The talk is suitable for graduate students.
ABSTRACT: The geometric link of a proper, unmixed ideal in a polynomial ring is another ideal such that their intersection is generated by a regular sequence, i.e., the union of their vanishing loci is a complete intersection. The 'most general' such link is called the generic link.
A classical research theme in linkage theory is to investigate what properties remain invariant along links. For example, height and the Cohen-Macaulay property are invariants of linkage. It is well-known that the generic link of a radical ideal is radical (even prime). This raises the question: Are either 'squarefreeness of the initial ideal' or 'F-purity' invariants of generic linkage? We answer this question in the negative.
On the other hand, under certain strong assumptions, we show that squarefreeness of the initial ideal, F-purity, and even the F-pure threshold are not only invariants of linkage but even invariants of residual intersections (a vast generalization of links).