unoriented plane
11Seifert fiber space — A Seifert fiber space is a 3 manifold together with a nice decomposition as a disjoint union of circles. In other words it is a S^1 bundle (circle bundle) over a 2 dimensional orbifold. Most small 3 manifolds are Seifert fiber spaces, and they… …
12Mapping class group — In mathematics, in the sub field of geometric topology, the mapping class group is an important algebraic invariant of a topological space. Briefly, the mapping class group is a discrete group of symmetries of the space. Contents 1 Motivation 2… …
13Complex cobordism — In mathematics, complex cobordism is a generalized cohomology theory related to cobordism of manifolds. Its spectrum is denoted by MU. It is an exceptionally powerful cohomology theory, but can be quite hard to compute, so often instead of using… …
14Mudcrack — Mud cracks in sewage sludge in Kos, Greece. Mudcracks (also known as desiccation cracks or mud cracks) are sedimentary structures formed as muddy sediment dries and contracts.[1] …
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