The Alexander polynomial coefficient inequality for rational cuspidal curves

Let CC be a rational cuspidal curve of degree dd with critical points z1,,znz_1,\ldots,z_n. Let K1,,KnK_1,\ldots,K_n be the corresponding links of singular points, with Alexander polynomials Δ1,,Δn\Delta_1,\ldots,\Delta_n, and let G1,,GnG_1,\ldots,G_n be their gap sequences. Set

g=G1+G2++Gng=|G_1|+|G_2|+\ldots+|G_n|

so that gg is the genus of KK. Write

Δ(t)=1+(t1)g+(t1)2j=02g2kl\Delta(t)=1+(t-1)g+(t-1)^2\sum_{j=0}^{2g-2}k_l

and let I=I1I2InI=I_1\diamond I_2\diamond\ldots\diamond I_n. The Alexander polynomial coefficient inequality. For every j=0,,d3j=0,\ldots,d-3,

kd(dj3)I(d(dj3)+1),k_{d(d-j-3)}\leq I\bigl(d(d-j-3)+1\bigr),

with equality for n=1n=1. This conjecture concerns restrictions on the Alexander polynomials and gap sequences of rational cuspidal curves; the equality case for one critical point was verified by Borodzik and Livingston, while the general case remains open in the supplied source.

Sources & referencesView supporting material

Primary source

Piotr Nayar and Barbara Pilat, “A note on the rational cuspidal curves”, arXiv:1406.3104 (2014).

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.