The compressibility of checkerboard surfaces of link diagrams
Zhiqiang Bao
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Consider the checkerboard surfaces defined by
some link diagrams. When they are not orientable, one considers the
boundary surfaces of their small regular neighborhoods. The
compressibility problem of these kinds of surfaces in the link
complements is studied. We defined normal positions for the
compressing discs. This brings up an algorithm to verify
compressibility directly from the link diagrams. As an application,
the algorithm is applied to diagrams in the knot tables. Examples of both
(infinitely many) examples of incompressible and (surprisingly)
completely compressible checkerboard surfaces of non-alternating knot
diagrams are discovered. The change of compressibility under
Reidermeister moves is also studied.
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