{ "id": "1412.6201", "version": "v1", "published": "2014-12-19T02:53:57.000Z", "updated": "2014-12-19T02:53:57.000Z", "title": "An Upper Bound on the Size of Obstructions for Bounded Linear Rank-Width", "authors": [ "Mamadou Moustapha Kanté", "O-joung Kwon" ], "comment": "28 pages, 1 figure", "categories": [ "math.CO" ], "abstract": "We provide a doubly exponential upper bound in $p$ on the size of forbidden pivot-minors for symmetric or skew-symmetric matrices over a fixed finite field $\\mathbb{F}$ of linear rank-width at most $p$. As a corollary, we obtain a doubly exponential upper bound in $p$ on the size of forbidden vertex-minors for graphs of linear rank-width at most $p$. This solves an open question raised by Jeong, Kwon, and Oum [Excluded vertex-minors for graphs of linear rank-width at most $k$. European J. Combin., 41:242--257, 2014]. We also give a doubly exponential upper bound in $p$ on the size of forbidden minors for matroids representable over a fixed finite field of path-width at most $p$. Our basic tool is the pseudo-minor order used by Lagergren [Upper Bounds on the Size of Obstructions and Interwines, Journal of Combinatorial Theory Series B, 73:7--40, 1998] to bound the size of forbidden graph minors for bounded path-width. To adapt this notion into linear rank-width, it is necessary to well define partial pieces of graphs and merging operations that fit to pivot-minors. Using the algebraic operations introduced by Courcelle and Kant\\'e, and then extended to (skew-)symmetric matrices by Kant\\'e and Rao, we define boundaried $s$-labelled graphs and prove similar structure theorems for pivot-minor and linear rank-width.", "revisions": [ { "version": "v1", "updated": "2014-12-19T02:53:57.000Z" } ], "analyses": { "subjects": [ "05C75", "G.2.2" ], "keywords": [ "bounded linear rank-width", "doubly exponential upper bound", "obstructions", "fixed finite field", "similar structure theorems" ], "note": { "typesetting": "TeX", "pages": 28, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1412.6201M" } } }