Linking numbers and Chen groups
نویسندگان
چکیده
منابع مشابه
Improving the Chen and Chen Result for Odd Perfect Numbers
If qα is the Euler factor of an odd perfect number N, then we prove that its so-called index σ(N/qα) � qα ≥ 32 × 5× 7 = 315. It follows that for any odd perfect number, the ratio of the non-Euler part to the Euler part is greater than 32 × 5× 7/2.
متن کاملTwisted Linking Numbers via Representations of Fundamental Groups
Using representations of fundamental groups, we introduce the concept of twisted linking numbers. If the corresponding representation is trivial, the twisted linking number coincides with the linking number. In the case of a nontrivial representation, however, this is not necessarily true, which implies that the twisted linking number can detect the nontriviality of an embedding of S. An exampl...
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In considering supercoils formed by closed double-stranded molecules of DNA certain mathematical concepts, such as the linking number and the twist, are needed. The meaning of these for a closed ribbon is explained and also that of the writhing number of a closed curve. Some simple examples are given, some of which may be relevant to the structure of chromatin.
متن کاملModular Cocycles and Linking Numbers
It is known that the 3-manifold SL(2,Z)\ SL(2,R) is diffeomorphic to the complement of the trefoil knot in S. E. Ghys showed that the linking number of this trefoil knot with a modular knot is given by the Rademacher symbol, which is a homogenization of the classical Dedekind symbol. The Dedekind symbol arose historically in the transformation formula of the logarithm of Dedekind’s eta function...
متن کاملLinking Numbers and Modular Cocycles
It is known that the 3-manifold SL(2,Z)\ SL(2,R) is diffeomorhic to the complement of the trefoil knot in S3. As is shown by E. Ghys the linking number of the trefoil with a modular knot associated to a hyperbolic conjugacy is related to the classical Dedekind symbol. These symbols arose historically in the transformation property of the logarithm of Dedekind’s eta function. In this paper we st...
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ژورنال
عنوان ژورنال: Topology and its Applications
سال: 1989
ISSN: 0166-8641
DOI: 10.1016/0166-8641(89)90098-9