Annulus Theorem
Let K_1^n and K_2^n be disjoint bicollared knots in R^(n+1) or S^(n+1) and let U denote the open region between them. Then the closure of U is a closed annulus S^n×[0,1]. Except for the case n=3, the theorem was proved by Kirby (1969).
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References
Kirby, R. C. "Stable Homeomorphisms and the Annulus Conjecture." Ann. Math. 89, 575-582, 1969.Rolfsen, D. Knots and Links. Wilmington, DE: Publish or Perish Press, p. 38, 1976.Referenced on Wolfram|Alpha
Annulus TheoremCite this as:
Weisstein, Eric W. "Annulus Theorem." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/AnnulusTheorem.html