Session 2. Algebraic Geometry

On the Abhyankar--Moh inequality

Arkadiusz Płoski, Kielce University of Technology, Poland
Let \(C\) be a complex affine algebraic curve of degree \(n > 1\) having only one branch at infinity \(\gamma\) and let \(r_{0}, r_{1},\dots,r_{h}\) be the \(n\)-sequence of the semigroup \(G\) of the branch \(\gamma\) defined as follows: \(r_{0}=n, r_{k}=\min\{r\in G: r\not\in\mathbb Nr_{o}+\dots+\mathbb Nr_{k-1}\} \) for \(k\ge1\) and \(G=\mathbb Nr_{o}+\dots+\mathbb Nr_{h}\). Then the Abhyankar--Moh inequality (see [1,2]) can be stated in the form \begin{equation}\tag{\(AM_{n}\)}\label{equatio} \gcd\{r_{0},\dots,r_{h-1}\}r_{h}<n^{2}. \end{equation} The aim of this talk is to present (see [3]) some results on the semigrups \(G\subset N\) of plane branches \(\gamma\) with property \eqref{equatio}. In particular we describe such semigroups with the maximum conductor.
References
  1. S.S.Abhyankar, T.T.Moh, Embeddings of the line in the plane . J. reine angew. Math.276 (1975), 148-166.
  2. E.García Barroso, A.Płoski, An approach to plane algebroid branches preprint arXiv:1208.0913 [math.AG].
  3. R.D.Barrolleta, E.R. García Barroso and A.Płoski, Appendix to [2] .
Print version