Y. Saad, Krylov Subspace Methods for Solving Large Unsymmetric Linear Systems, Mathematics of Computation, Vol. 37, No. 155 (Jul., 1981), pp. 105-126 ...

Two weeks ago, a modest-looking paper was uploaded to the arXiv preprint server with the unassuming title On the invariant subspace problem in Hilbert spaces.

Given a vector space V of homogeneous polynomials of the same degree over an infinite field, consider a generic subspace W of V. The main result of this paper is a lower-bound (in general sharp) for ...