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  2. 3-manifold - Wikipedia

    en.wikipedia.org/wiki/3-manifold

    The prime decomposition theorem for 3-manifolds states that every compact, orientable 3-manifold is the connected sum of a unique (up to homeomorphism) collection of prime 3-manifolds. A manifold is prime if it cannot be presented as a connected sum of more than one manifold, none of which is the sphere of the same dimension.

  3. Introduction to 3-Manifolds - Wikipedia

    en.wikipedia.org/wiki/Introduction_to_3-Manifolds

    Familiar examples of two-dimensional manifolds include the sphere, torus, and Klein bottle; this book concentrates on three-dimensional manifolds, and on two-dimensional surfaces within them. A particular focus is a Heegaard splitting, a two-dimensional surface that partitions a 3-manifold into two handlebodies. It aims to present the main ...

  4. Prime decomposition of 3-manifolds - Wikipedia

    en.wikipedia.org/wiki/Prime_decomposition_of_3...

    If is a prime 3-manifold then either it is or the non-orientable bundle over , or it is irreducible, which means that any embedded 2-sphere bounds a ball. So the theorem can be restated to say that there is a unique connected sum decomposition into irreducible 3-manifolds and fiber bundles of S 2 {\displaystyle S^{2}} over S 1 . {\displaystyle ...

  5. Category:3-manifolds - Wikipedia

    en.wikipedia.org/wiki/Category:3-manifolds

    Once a small subfield of geometric topology, the theory of 3-manifolds has experienced tremendous growth in the latter half of the 20th century. The methods used tend to be quite specific to three dimensions, since different phenomena occur for 4-manifolds and higher dimensions.

  6. Spherical 3-manifold - Wikipedia

    en.wikipedia.org/wiki/Spherical_3-manifold

    A prism manifold is a closed 3-dimensional manifold M whose fundamental group is a central extension of a dihedral group.. The fundamental group π 1 (M) of M is a product of a cyclic group of order m with a group having presentation

  7. The geometry and topology of three-manifolds - Wikipedia

    en.wikipedia.org/wiki/The_geometry_and_topology...

    The geometry and topology of three-manifolds is a set of widely circulated notes for a graduate course taught at Princeton University by William Thurston from 1978 to 1980 describing his work on 3-manifolds. They were written by Thurston, assisted by students William Floyd and Steven Kerchoff. [1]

  8. Medical device - Wikipedia

    en.wikipedia.org/wiki/Medical_device

    This article needs to be updated.The reason given is: the section related to E.U. needs further updates (esp. in sections 3.2 and 4.2.2) as the directives 93/42/EEC on medical devices and 90/385/EEC on active implantable medical devices have been fully repealed on 26 May 2021 by Regulation (EU) no. 2017/745 (MDR); furthermore, Brexit triggers updates in these sections (U.K. developed their own ...

  9. Seifert fiber space - Wikipedia

    en.wikipedia.org/wiki/Seifert_fiber_space

    A Seifert manifold is a closed 3-manifold together with a decomposition into a disjoint union of circles (called fibers) such that each fiber has a tubular neighborhood that forms a standard fibered torus.