Nguyên, Hoài-Minh2017-10-092017-10-092017-10-09201710.1016/j.crma.2017.10.007https://infoscience.epfl.ch/handle/20.500.14299/141074WOS:000414698400003We sharpen an estimate of [4] for the topological degree of continuous maps from a sphere Sdinto itself in the case d >= 2. This provides the answer for d >= 2 to a question raised by Brezis. The problem is still open for d = 1. (C) 2017 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.text::journal::journal article::research article