>>586
>>>585 構成も奇妙さもなんかキャッソン・ハンドルに似てる気がするのは気のせいか？

気のせいではないかもしれん
Alexander horned sphereについて、R. H. Bing の1952年の仕事がある（下記）
R. H. Bingは、ポアンカレ予想に取り組んでいた
Cassonもまた、3- and 4-dimensional topologyに取り組んでいたらしい
Bingの影響を受けている気がする

(参考)
https://en.wikipedia.org/wiki/Alexander_horned_sphere
Alexander horned sphere
The Alexander horned sphere is a pathological object in topology discovered by J. W. Alexander (1924). It is a particular topological embedding of a two-dimensional sphere in three-dimensional space. Together with its inside, it is a topological 3-ball, the Alexander horned ball, and so is simply connected; i.e., every loop can be shrunk to a point while staying inside. However, the exterior is not simply connected, unlike the exterior of the usual round sphere.
Impact on theory
The horned sphere, together with its inside, is a topological 3-ball, the Alexander horned ball, and so is simply connected; i.e., every loop can be shrunk to a point while staying inside. The exterior is not simply connected, unlike the exterior of the usual round sphere; a loop linking a torus in the above construction cannot be shrunk to a point without touching the horned sphere. This shows that the Jordan–Schönflies theorem does not hold in three dimensions, as Alexander had originally thought. Alexander also proved that the theorem does hold in three dimensions for piecewise linear/smooth embeddings. This is one of the earliest examples where the need for distinction between the categories of topological manifolds, differentiable manifolds, and piecewise linear manifolds became apparent.
Although the solid horned sphere is not a manifold, R. H. Bing showed that its double (which is the 3-manifold obtained by gluing two copies of the horned sphere together along the corresponding points of their boundaries) is in fact the 3-sphere.[2]
Generalizations
Other substantially different constructions exist for constructing such "wild" spheres.

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