A new paper purports to contain the final piece of a mathematical jigsaw puzzle: the invariant subspace problem ...

Octav Olteanu, Invariant Subspaces and Invariant Balls of Bounded Linear Operators, Bulletin mathématique de la Société des Sciences Mathématiques de Roumanie, Vol. 59(107), No. 3 (2016), pp. 261-271 ...

William G. Fleissner, Metacompact Subspaces of Products of Ordinals, Proceedings of the American Mathematical Society, Vol. 130, No. 1 (Jan., 2002), pp. 293-301 ...

In 50 years of searching, mathematicians found only one example of a “subspace design” in a vector space. A new proof reveals that there are infinitely more out there.