1. Introduction An efficient algorithm, HALO, is given to compute haloed line drawings of wire frame objects. (Haloed line drawings are described by Appel et al. 1 HALO has two parts: CUT and DRAW. CUT uses an adaptive grid to find all edge intersections. It overlays a square grid, whose fineness is a function of As computer aided design (CAD) deals with more complicated databases, it becomes c...

Matroid union and matroid intersection are closely related in the sense that one can be derived from the other. However they are from different perspectives and have different applications. To motivate matroid union theorem we state a well known theorem of Tutte and Nash-Williams on packing disjoint spanning trees in graphs. Theorem 1 (Nash-Williams and Tutte) An undirected multi-graph G = (V, ...

let $g$ be a finite group with the identity $e$‎. ‎the subgroup intersection graph $gamma_{si}(g)$ of $g$ is the graph with vertex set $v(gamma_{si}(g)) = g-e$ and two distinct vertices $x$ and $y$ are adjacent in $gamma_{si}(g)$ if and only if $|leftlangle xrightrangle capleftlangle yrightrangle|>1$‎, ‎where $leftlangle xrightrangle $ is the cyclic subgroup of $g$ generated by $xin g$‎. ‎in th...

The problem of detecting all possible digital line components contained in a given binary edge image is one of the most fundamental problems in pattern recognition and a great number of algorithms have been proposed under the name of Hough Transform [3, 4]. Most of them are based on the voting technique on a subdivided parameter space. Our basic idea is as follows: When we parameterize a line p...

In the EDGE CLIQUE COVER (ECC) problem, given a graph G and an integer k, we ask whether the edges of G can be covered with k complete subgraphs of G or, equivalently, whether G admits an intersection model on k-element universe. Gramm et al. [JEA 2008] have shown a set of simple rules that reduce the number of vertices of G to 2, and no algorithm is known with significantly better running time...

‎Let $R$ be a commutative ring with non-zero identity. ‎We describe all $C_3$‎- ‎and $C_4$-free intersection graph of non-trivial ideals of $R$ as well as $C_n$-free intersection graph when $R$ is a reduced ring. ‎Also, ‎we shall describe all complete, ‎regular and $n$-claw-free intersection graphs. ‎Finally, ‎we shall prove that almost all Artin rings $R$ have Hamiltonian intersection graphs. ...

PM**£(*') f° r h£rS$2 where h ( < ^ ) is the point nearest to s* at which €(li)«<r(4j). If $(52)==<r(52), then let h~$%. For r<t2 let p(r) =p(^)+log log log fc — log log log r for Ui^r^h where #1 (<*2) is the point of intersection of y—p with y = p (£2) + log log log fe—log log log r. Let p(r)~p for r i^ rgwi . It is always possible to choose H SO large that r\<ti\. We repeat the procedure and ...

Article history: Received 14 November 2009 Received in revised form 29 April 2010 Accepted 6 May 2010

Given a simple generalized polygonA of line segments and arcs that is free to move and rotate and an oriented monotone chainB composed of smooth parametric curved edges, the positions and orientations forA to gouge-freely contactB (i.e., the contact configurations) is a C0 continuous surface in a three dimensional space R3. Past results either limitB to be polygonal or depend on the very compli...