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Oliviero Malech

Publications and source records attributed to Oliviero Malech.

3 recordsLinked to original sources

Internal and external stabilization of exotic surfaces in 4-manifolds

We show that many explicit examples of exotic pairs of surfaces in a smooth 4-manifold become smoothly isotopic after one external stabilization with $S^2\times S^2$ or $CP^2\#\overline{CP^2}$. Our results cover surfaces produced by rim-surgery, twist-rim-surgery, annulus rim-surgery, as well as infinite families of nullhomologus surfaces and examples with non-cyclic fundamental group of the complement. A special attention is given to the identification of the stabilizing manifold and its dependence on the choices in the construction of the surface. The main idea of this note is given by relating internal and external stabilization, and most of the results, but not all, are proved using this relation. Moreover, we show that the 2-links in the exotic family from the recent work of Bais, Benyahia, Malech and Torres are brunnian, under some additional assumptions about the construction.

math.GT

A recipe for exotic 2-links in closed 4-manifolds whose components are topological unknots

We describe a construction procedure of infinite sets of $2$-links in closed simply connected 4-manifolds that are topologically isotopic, smoothly inequivalent and componentwise topologically unknotted. These 2-links are the first examples of such kind in the literature. The examples provided have surface and free groups as their 2-link groups. We also point out an exotic Brunnian behaviour of such families, which highlights the important role of linking in creating exotic phenomena.

math.GT

The multiple fibration problem for Seifert 3-orbifolds

We conclude the multiple fibration problem for closed orientable Seifert three-orbifolds, namely the determination of all the inequivalent fibrations that such an orbifold may admit. We treat here geometric orbifolds with geometries $\mathbb R^3$ and $\mathbb S^2\times\mathbb R$ and bad orbifolds (hence non-geometric), since the only other geometry for which the multiple fibration phenomenon occurs, namely $\mathbb S^3$, has been treated before by the second and third author. For the geometry $\mathbb R^3$ we recover, by direct and geometric arguments, the computer-assisted results obtained by Conway, Delgado-Friedrichs, Huson and Thurston.

math.GT