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On Prime Immersions of S1 into R2

Published online by Cambridge University Press:  20 November 2018

John R. Martin*
Affiliation:
University of Saskatchewan, Saskatoon, Saskatchewan
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A C1-mapping ƒ from the oriented circle S1 into the oriented plane R2 such that f f’ (t) ≠ 0 for all t is called a regular immersion. We call a point p in Im f a double point if f-1(p) is a two element set with the corresponding tangent vectors being linearly independent. A regular immersion which is one-to-one except at a finite number of points whose images are double points is called a normal immersion. The work of Whitney [7], Titus [3] and Verhey [6] shows that the normal immersions form a dense open subset in the space of regular immersions with the usual C1-topology, and can be characterized up to diffeomorphic equivalence by a combinatorial invariant called the intersection sequence.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1976

References

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