منابع مشابه
Seasonal variations of polygonal thermal contraction crack patterns in a south polar trough, Mars
[1] We present observations of seasonal variations in polygonal crack patterns located in a polar trough on the south polar cap of Mars; previously, there was no direct observation showing that these patterns change. Polygonal patterns on Mars are attributed to thermal contraction cracking, which is commonly observed in periglacial environments on Earth. In this paper we discuss observations ba...
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Consider a planar linkage, consisting of disjoint polygonal arcs and cycles of rigid bars joined at incident endpoints (polygonal chains), with the property that no cycle surrounds another arc or cycle. We prove that the linkage can be continuously moved so that the arcs become straight, the cycles become convex, and no bars cross while preserving the bar lengths. Furthermore, our motion is pie...
متن کاملStraighting Polygonal Arcs and Convexifying Polygonal Cycles
Consider a planar linkage, consisting of disjoint polygonal arcs and cycles of rigid bars joined at incident endpoints (polygonal chains), with the property that no cycle surrounds another arc or cycle. We prove that the linkage can be continuously moved so that the arcs become straight, the cycles become convex, and no bars cross while preserving the bar lengths. Furthermore, our motion is pie...
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We develop a valuation theory for generalized polygons similar to the existing theory for dense near polygons. This valuation theory has applications for the study and classification of generalized polygons that have full subpolygons as subgeometries.
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In the article the formal characterization of triangular numbers (famous from [15] and words “EYPHKA! num = ∆ + ∆ + ∆”) [17] is given. Our primary aim was to formalize one of the items (#42) from Wiedijk’s Top 100 Mathematical Theorems list [33], namely that the sequence of sums of reciprocals of triangular numbers converges to 2. This Mizar representation was written in 2007. As the Mizar lang...
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ژورنال
عنوان ژورنال: Bulletin of the American Mathematical Society
سال: 1938
ISSN: 0002-9904
DOI: 10.1090/s0002-9904-1938-06800-0