Conway algebras and skein equivalence of links
Conway algebras and skein equivalence of links
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DOI:
10.1090/s0002-9939-1987-0894448-2
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发表时间:
1987-04
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影响因子:
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通讯作者:
J. Przytycki;Pawel Traczyk
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文献类型:
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作者:
J. Przytycki;Pawel Traczyk
We consider a class of pairs of links which are not skein equivalent but have the same invariant in every Conway algebra. 1. Conway algebras. We will first recall the notion of Conway algebra as introduced in [PT]. DEFINITION 1.1. A Conway algebra is an algebra A with a sequence of 0argument operations a1, a2, ... and two 2-argument operations I and *, which satisfy the following conditions: Ci. anIan+1 = ani C2. an * an+1 = an (Cl and C2 are initial conditions properties), C3. (alb)I(cld) = (alc)I(bld), C4. (aIb) * (cId) = (a * c)I(b * d) (C3, C4 and C5 are transposition properties), C5. (a*b) * (c*d) = (a*c) * (b*d), C6. (alb) * b = a, C7. (a*b)lb=a. As shown in [PT] every Conway algebra yields an invariant of links which is constant on skein equivalence classes (skein invariant). It is uniquely determined by the following conditions: AT, = an (initial relations), AL+ = AL_ JALo and AL_ = AL+ * ALO (Conway relations). Here Tn denotes a trivial link of n components and L+, L-, and LO are diagrams of oriented links identical except near one crossing point (see Figure 1.1).