منابع مشابه
Ribbon Tile Invariants
Let T be a finite set of tiles, and B a set of regions Γ tileable by T. We introduce a tile counting group G(T,B) as a group of all linear relations for the number of times each tile τ ∈ T can occur in a tiling of a region Γ ∈ B. We compute the tile counting group for a large set of ribbon tiles, also known as rim hooks, in a context of representation theory of the symmetric group. The tile cou...
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Ribbon tiles are polyominoes consisting of n squares laid out in a path, each step of which goes north or east. Tile invariants were rst introduced in P1], where a full basis of invariants of ribbon tiles was conjectured. Here we present a complete proof of the conjecture, which works by associating ribbon tiles with certain polygons in the complex plane, and deriving invariants from the signed...
متن کاملTile invariants: new horizons
Let T be a nite set of tiles. The group of invariants G (T), introduced by the author P], is a group of linear relations between the number of copies of tiles in tilings of the same region. We survey known results about G , the height function approach, the local move property, various applications and special cases.
متن کاملRibbon Concordance of Surface-knots via Quandle Cocycle Invariants
We give necessary conditions of a surface-knot to be ribbon concordant to another, by introducing a new variant of the cocycle invariant of surface-knots in addition to using the invariant already known. We demonstrate that twist-spins of some torus knots are not ribbon concordant to their orientation reversed images.
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At the high resolutions attainable with the new generation space-borne sensors, the focus moves increasingly from spectral characteristics to geometric features. This trend is even more evident for urban areas which tend to show an unpaired concentration of linear features with respect to any other land cover. This naturally applies to both optical and radar images, and suggests one may use loc...
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ژورنال
عنوان ژورنال: Transactions of the American Mathematical Society
سال: 2000
ISSN: 0002-9947,1088-6850
DOI: 10.1090/s0002-9947-00-02666-0