1,468 research outputs found

    Some non-existence results for distance-jj ovoids in small generalized polygons

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    We give a computer-based proof for the non-existence of distance-22 ovoids in the dual split Cayley hexagon H(4)D\mathsf{H}(4)^D. Furthermore, we give upper bounds on partial distance-22 ovoids of H(q)D\mathsf{H}(q)^D for q∈{2,4}q \in \{2, 4\}.Comment: 10 page

    Characterizations of the Suzuki tower near polygons

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    In recent work, we constructed a new near octagon G\mathcal{G} from certain involutions of the finite simple group G2(4)G_2(4) and showed a correspondence between the Suzuki tower of finite simple groups, L3(2)<U3(3)<J2<G2(4)<SuzL_3(2) < U_3(3) < J_2 < G_2(4) < Suz, and the tower of near polygons, H(2,1)⊂H(2)D⊂HJ⊂G\mathrm{H}(2,1) \subset \mathrm{H}(2)^D \subset \mathsf{HJ} \subset \mathcal{G}. Here we characterize each of these near polygons (except for the first one) as the unique near polygon of the given order and diameter containing an isometrically embedded copy of the previous near polygon of the tower. In particular, our characterization of the Hall-Janko near octagon HJ\mathsf{HJ} is similar to an earlier characterization due to Cohen and Tits who proved that it is the unique regular near octagon with parameters (2,4;0,3)(2, 4; 0, 3), but instead of regularity we assume existence of an isometrically embedded dual split Cayley hexagon, H(2)D\mathrm{H}(2)^D. We also give a complete classification of near hexagons of order (2,2)(2, 2) and use it to prove the uniqueness result for H(2)D\mathrm{H}(2)^D.Comment: 20 pages; some revisions based on referee reports; added more references; added remarks 1.4 and 1.5; corrected typos; improved the overall expositio

    A new near octagon and the Suzuki tower

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    We construct and study a new near octagon of order (2,10)(2,10) which has its full automorphism group isomorphic to the group G2(4):2\mathrm{G}_2(4){:}2 and which contains 416416 copies of the Hall-Janko near octagon as full subgeometries. Using this near octagon and its substructures we give geometric constructions of the G2(4)\mathrm{G}_2(4)-graph and the Suzuki graph, both of which are strongly regular graphs contained in the Suzuki tower. As a subgeometry of this octagon we have discovered another new near octagon, whose order is (2,4)(2,4).Comment: 24 pages, revised version with added remarks and reference

    On semi-finite hexagons of order (2,t)(2, t) containing a subhexagon

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    The research in this paper was motivated by one of the most important open problems in the theory of generalized polygons, namely the existence problem for semi-finite thick generalized polygons. We show here that no semi-finite generalized hexagon of order (2,t)(2,t) can have a subhexagon HH of order 22. Such a subhexagon is necessarily isomorphic to the split Cayley generalized hexagon H(2)H(2) or its point-line dual HD(2)H^D(2). In fact, the employed techniques allow us to prove a stronger result. We show that every near hexagon S\mathcal{S} of order (2,t)(2,t) which contains a generalized hexagon HH of order 22 as an isometrically embedded subgeometry must be finite. Moreover, if H≅HD(2)H \cong H^D(2) then S\mathcal{S} must also be a generalized hexagon, and consequently isomorphic to either HD(2)H^D(2) or the dual twisted triality hexagon T(2,8)T(2,8).Comment: 21 pages; new corrected proofs of Lemmas 4.6 and 4.7; earlier proofs worked for generalized hexagons but not near hexagon

    Financial Outlook For A Troubled Global Industry

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    In early 2005, British Airways plans to start implementing its corporate restructuring plan with a sizeable layoff involved in response to the pressures from the competition at home and abroad. Virgin Atlantic, on the other hand, decided to test a unique approach towards name recognition of its airline by having its founding chair, Sir Richard Branson, participate in a Fall season TV Reality show in America. Their American counterparts are responding with union negotiation, layoffs, starting no-frills, low cost airlines among other strategic responses to meet the competitive pressures head on. This paper analyzes the severe threat to the airlines industry in a &ldquo; pre and post 9/11&rdquo; global economic&nbsp; perspective to focus on the future of the revamped industry

    Some contributions to incidence geometry and the polynomial method

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