Improved lower-bound conjecture for Hilbert–Kunz multiplicities

Let (A,m,k)(A,\mathfrak{m}, k) be a formally unmixed non-regular local ring of dimension d1d \geq 1 with algebraically closed residue field. Let m1m \geq 1 be an integer, and let Ap,dA_{p,d} be the simple singularity defined above. Improved lower-bound conjecture. If d=2m1d=2m-1, then either

A^Ap,d\widehat{A}\cong A_{p,d}

or

eHK(A)>2m2m1.\operatorname{e_{HK}}(A)>\frac{2^m}{2^m-1}.

If d=2md=2m, then either

A^Ap,d\widehat{A}\cong A_{p,d}

or

eHK(A)>2m+12m.\operatorname{e_{HK}}(A)>\frac{2^m+1}{2^m}.

This strengthens the proposed universal lower bounds suggested by the known formulas in characteristic two. It is presented as an improvement of the preceding conjecture and remains open in general.

Sources & referencesView supporting material

Primary source

Jack Jeffries, Yusuke Nakajima, Ilya Smirnov, Kei-ichi Watanabe and Ken-ichi Yoshida, “Lower bounds on Hilbert–Kunz multiplicities and maximal F-signatures”, arXiv:2002.06166 (2022).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.