%0 Journal Article %T The least singular value of a random square matrix is O(n^{-1/2}) %A Mark Rudelson %A Roman Vershynin %J Mathematics %D 2008 %I arXiv %X Let A be a matrix whose entries are real i.i.d. centered random variables with unit variance and suitable moment assumptions. Then the smallest singular value of A is of order n^{-1/2} with high probability. The lower estimate of this type was proved recently by the authors; in this note we establish the matching upper estimate. %U http://arxiv.org/abs/0805.3407v1