{ "id": "1307.4837", "version": "v1", "published": "2013-07-18T06:11:48.000Z", "updated": "2013-07-18T06:11:48.000Z", "title": "On the fundamental groups of non-generic $\\mathbb{R}$-join-type curves", "authors": [ "Christophe Eyral", "Mutsuo Oka" ], "comment": "21 pages, 19 figures", "categories": [ "math.AG" ], "abstract": "An \\emph{$\\mathbb{R}$-join-type curve} is a curve in $\\mathbb{C}^2$ defined by an equation of the form \\begin{equation*} a\\cdot\\prod_{j=1}^\\ell (y-\\beta_j)^{\\nu_j} = b\\cdot\\prod_{i=1}^m (x-\\alpha_i)^{\\lambda_i}, \\end{equation*} where the coefficients $a$, $b$, $\\alpha_i$ and $\\beta_j$ are \\emph{real} numbers. For generic values of $a$ and $b$, the singular locus of the curve consists of the points $(\\alpha_i,\\beta_j)$ with $\\lambda_i,\\nu_j\\geq 2$ (so-called \\emph{inner} singularities). In the non-generic case, the inner singularities are not the only ones: the curve may also have \\emph{`outer'} singularities. The fundamental groups of (the complements of) curves having only inner singularities are considered in \\cite{O}. In the present paper, we investigate the fundamental groups of a special class of curves possessing outer singularities.", "revisions": [ { "version": "v1", "updated": "2013-07-18T06:11:48.000Z" } ], "analyses": { "subjects": [ "14H30", "14H20", "14H45", "14H50" ], "keywords": [ "fundamental groups", "join-type curve", "inner singularities", "curves possessing outer singularities", "special class" ], "note": { "typesetting": "TeX", "pages": 21, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1307.4837E" } } }