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Surgery description of colored knots
The pair (K,r) consisting of a knot K and a surjective map r from the knot
group onto a dihedral group is said to be a p-colored knot. D. Moskovich
conjectured that for any odd prime p there are exactly p equivalence classes of
p-colored knots up to surgery along unknots in the kernel of the coloring. We
show that there are at most 2p equivalence classes. This is a vast improvement
upon the previous results by Moskovich for p=3, and 5, with no upper bound
given in general. T. Cochran, A. Gerges, and K. Orr, in "Dehn surgery
equivalence relations of 3-manifolds", define invariants of the surgery
equivalence class of a closed 3-manifold M in the context of bordisms. By
taking M to be 0-framed surgery of the 3-sphere along K we may define
Moskovich's colored untying invariant in the same way as the Cochran-Gerges-Orr
invariants. This bordism definition of the colored untying invariant will be
then used to establish the upper bound.Comment: 41 pages, 23 figures (Version 3) Minor revisions and typos fixed.
Proofs of Propositions 4.1 and 4.8 revise
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Half a Million Older Californians Living Alone Unable to Make Ends Meet
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Surgery description of colored knots
By a knot, or link, we mean a circle, or a collection of circles, embedded in the three-sphere S3. The study of knots is a very rich subject and plays a key role in the area of low-dimensional topology. In fact, a theorem of W.B.R. Lickorish and A.D. Wallace states that any three-dimensional manifold may be described by Dehn surgery along a link which is the process of removing the link from S3 and then gluing it back in a way that possibly changes the resulting manifold. In this dissertation, we will be interested in the pair (K, Ï) consisting of a knot K and a surjective map Ï from the knot group onto a dihedral group of order 2p called a coloring. Such an object is said to be a p-colored knot. In Surgery untying of colored knots , D. Moskovich conjectures that for any odd prime p there are exactly p equivalence classes of p-colored knots up to surgery which preserves colorability. This is an analog to the classical result that every knot has a surgery description or equivalently that every knot is surgery equivalent to the unknot if we place fewer restrictions on the allowed surgery curves. We show that there are at most 2p equivalence classes for p any odd number. This is an improvement upon the previous results by Moskovich for p = 3, and 5, with no upper bound given in general. We do this by defining a new invariant, or an algebraic object associated to a p-colored knot, which is complete in the sense that two p-colored knots are surgery equivalent if and only if they both have the same value of this invariant. The complete invariant consists of Moskovichâs colored untying invariant redefined in the same way as the three-manifold invariants developed by T. Cochran, A. Gerges, and K. Orr, and another object we call the η invariant. We also extend these methods to give similar results for A4-colored knots which have representations onto the alternating group on four letters
Contrasting Inequalities: Comparing Correlates of Health in Canada and the United States
Comparative health studies consistently find that Canadians on average are healthier than Americans. Comparing health status within and between Canada and the United States provides key insights into the distribution of inequalities in these two countries. Canadaâs universal health care insurance system contrasts with the mixed system of the United States: universal care for seniors, private health care insurance for many, and no or intermittent coverage for others. These countries are also notably different in the extent of income and racial/ethnic inequalities. It is within this context that this study compares the relative strength of the relationships between social, economic, and demographic factors (sex, age, marital status, income, education, country of birth, and race/ethnicity) and health status in Canada and the United States. Evidence drawn from the 2002-2003 Joint Canada/United States Survey of Health reveals that the correlations between these factors, above all country of birth and race/ethnicity, and health are relatively stronger in the United States, reflecting differences in health care access and racial/ethnic-based inequalities between the countries. The study findings are suggestive of the effects of universal access to health care and more equitable distribution of other social resources in protecting the health of the general population.self-reported health, United States, Canada, health insurance, income, race, ethnicity, age, sex
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