We obtain a near-tight bound of O(n), for any ε > 0, on the complexity of the overlay of the minimization diagrams of two collections of surfaces in four dimensions. This settles a long-standing problem in the theory of arrangements, most recently cited by Agarwal and Sharir [3, Open Problem 2], and substantially improves and simplifies a result previously published by the authors [17]. Our bou...

Two skew cyclic codes can be equivalent for the Hamming metric only if they have the same length, and only the zero code is degenerate. The situation is completely different for the rank metric, where lengths of codes correspond to the number of outgoing links from the source when applying the code on a network. We study rank equivalences between skew cyclic codes of different lengths and, with...

In this paper, we study the arithmetics of skew polynomial rings over finite fields, mostly from an algorithmic point of view. We give various algorithms for fast multiplication, division and extended Euclidean division. We give a precise description of quotients of skew polynomial rings by a left principal ideal, using results relating skew polynomial rings to Azumaya algebras. We use this des...

Many techniques have been developed for detecting the dominant skew angle of printed documents [2]. However sometimes more than one skew angle is represented in the document image. Baird [3] points out that the paste-up of text columns may result in slightly (but significantly) different skew angles and notes the importance of segmenting the columns first in order that individual skew correctio...

Strong starters and skew starters have been widely used in various combinatorial designs. In particular skew balanced starters and symmetric skew balanced starters are crucially used in the construction of completely balanced Howell rotations. Let n = 2mfc + 1 be an odd prime power where m > 2 and k is an odd number. The existence of symmetric skew balanced starters for GF(n) has been proved fo...

This paper aims to investigate properties of involution palindrome languages. Let θ be either a morphic or antimorphic involution. we show that if θ is an antimorphic involution, then the set of all θ-palindrome words is a proper subset of all skew θ-palindrome words. We give a characterization for that a word is skew θ-palindrome. That is, A word is skew θ-palindrome if and only if it is a pro...

Accurate clock skew budgets are important for microprocessor designers to avoid holdtime failures and to properly allocate resources when optimizing global and local paths. Many published clock skew budgets neglect voltage jitter and process variation, which are becoming dominant factors in otherwise balanced H-trees. However, worst-case process variation assumptions are severely pessimistic. T...

Cluster automorphisms have been shown to have links to the mapping class groups of surfaces, maximal green sequences and to exchange graph automorphisms for skew-symmetric cluster algebras. In this paper we generalise these results to the skew-symmetrizable case by introducing a marking on the exchange graph. Many skew-symmetrizable matrices unfold to skew-symmetric matrices and we consider how...

Huber, Krokhin, and Powell (2013) introduced a concept of skew bisubmodularity, as a generalization of bisubmodularity, in their complexity dichotomy theorem for valued constraint satisfaction problems over the three-value domain, and Huber and Krokhin (2014) showed the oracle tractability of minimization of skew-bisubmodular functions. Fujishige, Tanigawa, and Yoshida (2014) also showed a min-...

When a document is fed to a scanner either mechanically or by a human operator for digitization, it suffers from some degrees of skew or tilt. Skew angle detection is an important component of any Optical Character Recognition (OCR) and Document Analysis System. In this paper we present a novel skew estimation technique for document images. The method uses Boundary Growing (BG) technique, Thinn...