文章基本信息

标题：Coverability in 1-VASS with Disequality Tests
本地全文：下载
作者：Shaull Almagor ; Nathann Cohen ; Guillermo A. Prez 等
期刊名称：LIPIcs : Leibniz International Proceedings in Informatics
电子版ISSN：1868-8969
出版年度：2020
卷号：171
页码：38:1-38:20
DOI：10.4230/LIPIcs.CONCUR.2020.38
出版社：Schloss Dagstuhl -- Leibniz-Zentrum fuer Informatik
摘要：We study a class of reachability problems in weighted graphs with constraints on the accumulated weight of paths. The problems we study can equivalently be formulated in the model of vector addition systems with states (VASS). We consider a version of the vertex-to-vertex reachability problem in which the accumulated weight of a path is required always to be non-negative. This is equivalent to the so-called control-state reachability problem (also called the coverability problem) for 1-dimensional VASS. We show that this problem lies in NC: the class of problems solvable in polylogarithmic parallel time. In our main result we generalise the problem to allow disequality constraints on edges (i.e., we allow edges to be disabled if the accumulated weight is equal to a specific value). We show that in this case the vertex-to-vertex reachability problem is solvable in polynomial time even though a shortest path may have exponential length. In the language of VASS this means that control-state reachability is in polynomial time for 1-dimensional VASS with disequality tests.
关键词：Reachability; Vector addition systems with states; Weighted graphs