Abstract:PACS. 71.55 -i -Impurity and defect levels. PACS. 72.20Ht -High field and nonlinear effects.PACS. 72.40 + w -Photoconduction and photovoltaic effects: photodielectric effects.Abstract. -The ionisation of deep impurity centres in germanium has been observed with radiation in the terahertz range where the photon energy is much less than the binding energy of the impurities. It is shown that for not too high radiation intensities the ionisation is caused by the Poole-Frenkel effect. As in the well-known case of d… Show more
“…Racks and quandles have been studied in, for example, [1,13,20,21,23]. The axioms for a quandle correspond respectively to the Reidemeister moves of type I, II, and III (see [13,21], for example).…”
The quandle homology theory is generalized to the case when the coefficient groups admit the structure of Alexander quandles, by including an action of the infinite cyclic group in the boundary operator. Theories of Alexander extensions of quandles in relation to low dimensional cocycles are developed in parallel to group extension theories for group cocycles. Explicit formulas for cocycles corresponding to extensions are given, and used to prove non-triviality of cohomology groups for some quandles. The corresponding generalization of the quandle cocycle knot invariants is given, by using the Alexander numbering of regions in the definition of statesums. The invariants are used to derive information on twisted cohomology groups.
“…Racks and quandles have been studied in, for example, [1,13,20,21,23]. The axioms for a quandle correspond respectively to the Reidemeister moves of type I, II, and III (see [13,21], for example).…”
The quandle homology theory is generalized to the case when the coefficient groups admit the structure of Alexander quandles, by including an action of the infinite cyclic group in the boundary operator. Theories of Alexander extensions of quandles in relation to low dimensional cocycles are developed in parallel to group extension theories for group cocycles. Explicit formulas for cocycles corresponding to extensions are given, and used to prove non-triviality of cohomology groups for some quandles. The corresponding generalization of the quandle cocycle knot invariants is given, by using the Alexander numbering of regions in the definition of statesums. The invariants are used to derive information on twisted cohomology groups.
“…In order for this notion to be topological we require a special kind of permutation which we call a Coloring Automorphism. These are permutations which comply with the coloring operation, a * b := 2b − a in a pre-assigned modulus m. This operation generalizes to the quandle operation, generalizing also the notion of coloring ( [7,13]). In the particular instance a * b = 2b − a we are dealing with the so-called dihedral quandles, one per integer modulus m.…”
Section: Equivalence Classes Of Coloringsmentioning
confidence: 99%
“…In the context of quandles this work has to do with homomorphisms from the fundamental quandle of the knot to the dihedral quandles ( [7,13]). We organize these homomorphisms into equivalence classes.…”
For any link and for any modulus m we introduce an equivalence relation on the set of nontrivial m-colorings of the link (an m-coloring has values in Z/mZ). Given a diagram of the link, the equivalence class of a non-trivial m-coloring is formed by each assignment of colors to the arcs of the diagram that is obtained from the former coloring by a permutation of the colors in the arcs which preserves the coloring condition at each crossing. This requirement implies topological invariance of the equivalence classes. We show that for a prime modulus the number of equivalence classes depends on the modulus and on the rank of the coloring matrix (with respect to this modulus).
“…A quandle (see Fenn and Rourke [3], Joyce [5] or Matveev [10]) is a set X with a binary operation .x; y/ 7 ! x y such that (i) for any x 2 X , it holds that x x D x , (ii) for any x; y 2 X , there exists a unique z 2 X such that z y D x , and (iii) for any x; y; z 2 X , it holds that .x y / z D .x z / .y z / .…”
Section: Symmetric Quandles and Their Cocyclesmentioning
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