In this paper, by using properties of Baer subplanes, we describe the construction of a minimal blocking set in the Hall plane of order q2 of size q2 + 2q + 2 admitting ∗This author has been supported as a postdoctoral fellow of the Research Foundation Flanders (Belgium) (FWO). †This author was supported by a Visiting Professor grant of the Special Research Fund Ghent University (BOF project nu...

We consider the natural generalizations of blocking and antiblocking polyhedra in infinite dimensions, and study issues related to duality and integrality of extreme points for these sets. Using appropriate finite truncations we give conditions under which complementary slackness holds for primal-dual pairs of the infinite linear programming problems associated with infinite blocking and anti-b...

Channel graphs have been widely used in the study of blocking networks. In this paper, we show that a bit permutation network has a unique channel graph if and only if it is connected, and two connected bit permutation networks are isomorphic if and only if their channel graphs are isomorphic. c © 2001 Elsevier Science B.V. All rights reserved.

We consider a blocking problem: fire propagates on a half plane with unit speed in all directions. To block it, a barrier can be constructed in real time, at speed σ. We prove that the fire can be entirely blocked by the wall, in finite time, if and only if σ > 1. The proof relies on a geometric lemma of independent interest. Namely, let K ⊂ IR2 be a compact, simply connected set with smooth bo...

A small minimal k-blocking set B in PG(n, q), q = pt, p prime, is a set of less than 3(qk + 1)/2 points in PG(n, q), such that every (n − k)-dimensional space contains at least one point of B and such that no proper subset of B satisfies this property. The linearity conjecture states that all small minimal k-blocking sets in PG(n, q) are linear over a subfield Fpe of Fq. Apart from a few cases,...

We propose and study dynamic versions of the classical flexibility constructs skip and block and motivate and define a formal semantics for them. We show that our semantics for dynamic blocking is a generalization of classical dead-path-elimination and solves the long-standing open problem to define deadpath elimination for cyclic workflows. This gives rise to a simple and fully local semantics...

Context. The problem of performance and scalability of web applications is challenged by most of the software companies. It is difficult to maintain the performance of a web application while the number of users is continuously increasing. The common solution for this problem is scalability. A web application can handle incoming and outgoing requests using blocking or non-blocking Input/Output ...

In this paper, we show that a small minimal k-blocking set in PG(n, q), q = p, h ≥ 1, p prime, p ≥ 7, intersecting every (n−k)-space in 1 (mod q) points, is linear. As a corollary, this result shows that all small minimal k-blocking sets in PG(n, p), p prime, p ≥ 7, are Fp-linear, proving the linearity conjecture (see [7]) in the case PG(n, p), p prime, p ≥ 7.

This paper contains two main results relating to the size of a multiple blocking set in PG(2, q). The first gives a very general lower bound, the second a much better lower bound for prime planes. The latter is used to consider maximum sizes of (k, n)-arcs in PG(2, 11) and PG(2, 13), some of which are determined. In addition, a summary is given of the value of mn(2, q) for q ≤ 13.

A stability theorem says that a nearly extremal object can be obtained from an extremal one by “small changes”. In this paper, we study the relation of sets having few 0-secants and blocking sets.