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Immersions and Embeddings Up to Cobordism

Published online by Cambridge University Press:  20 November 2018

Richard L. W. Brown*
Affiliation:
York University, Toronto, Ontario
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In 1944 Whitney proved that any differentiable n-manifold (n ≧ 2) can be (differentiably) immersed in R2n–1[15] and embedded in R2n [14]. Whitney's results are best possible when n = 2r. (One uses a simple argument involving the dual Stiefel-Whitney classes of real projective space Pn. See [9, pp. 14, 15].) However, there is a widely known conjecture that any R-manifold (n ≧ 2) immerses in R2nα(n) and embeds in R2nα(n)+1. Here, α(n) denotes the number of ones in the binary expansion of n. We prove (Theorem 5.1) that every compact manifold is cobordant to a manifold that immerses in (2nα(n))-space and embeds in (2nα(n) + 1)-space. (See § 1 for the definition of cobordant manifolds.) It is well known that if the conjecture were true it would be the best possible result.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1971

References

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