2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/58642A sharp explicit estimate is proved for the difference $e^β-α$ when $α$ and $β$ are nonzero algebraic numbers.17 pages. See also http://www.math.jussieu.fr/~miw/articles/ps/Nesterenko.ps and http://www.math.jussieu.fr/~nesteren/Number Theory11J82On the approximation of the values of exponential function and logarithm by algebraic numberstext