منابع مشابه
Non-Crossing Frameworks with Non-Crossing Reciprocals
We study non-crossing frameworks in the plane for which the classical reciprocal on the dual graph is also non-crossing. We give a complete description of the self-stresses on non-crossing frameworks G whose reciprocals are non-crossing, in terms of: the types of faces (only pseudo-triangles and pseudo-quadrangles are allowed); the sign patterns in the stress on G; and a geometric condition on ...
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The crossing number of a graph is the minimum number of edge intersections in a plane drawing of a graph, where each intersection is counted separately. If instead we count the number of pairs of edges that intersect an odd number of times, we obtain the odd crossing number. We show that there is a graph for which these two concepts differ, answering a well-known open question on crossing numbe...
متن کاملCrossing number, pair-crossing number, and expansion
The crossing number crðGÞ of a graph G is the minimum possible number of edge crossings in a drawing of G in the plane, while the pair-crossing number pcrðGÞ is the smallest number of pairs of edges that cross in a drawing of G in the plane. While crðGÞXpcrðGÞ holds trivially, it is not known whether a strict inequality can ever occur (this question was raised by Mohar and Pach and Tóth). We ai...
متن کاملCrossing the threshold of Iranian TEFL
Teaching English in an Iranian and Islamic culture poses complex questions for both teachers and learners. In this paper, the authors intend to shed light on what it means to teach English as a foreign language (TEFL) in an Islamic-Iranian context. Having reviewed the colonial and postmodern views of English language teaching, the authors took a look beyond the current ...
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ژورنال
عنوان ژورنال: Pragmatics and Society
سال: 2018
ISSN: 1878-9714,1878-9722
DOI: 10.1075/ps.16028.jaw