A lower bound on Seshadri constants of hyperplane bundles on threefolds

We give the lower bound on Seshadri constants for the case of very ample line bundles on threefolds. We consider the situation when the Seshadri constant is strictly less than 2 and give a version of Bauer’s theorem (Math Ann 313(3):547–583, 1999, Theorem 2.1) for singular surfaces so we can prove the same result for smooth threefolds.