A longstanding conjecture claims that the Diophantine equationformula herehas finitely many solutions and, maybe, only those given byformula hereAmong the known results, let us mention that Ljunggren [9] solved (1) completely
when q = 2 and that very recently Bugeaud et al. [3] showed that (1) has no solution
when x is a square. For more information and in particular for finiteness type results
under some extra hypotheses, we refer the reader to Nagell [11], Shorey & Tijdeman
[16, 17] and to the recent survey of Shorey [15]. One of the main tools used in most
of the proofs is Baker's theory of linear form in archimedean logarithms of algebraic
numbers and especially a dramatic sharpening obtained when the algebraic numbers
involved are closed to 1. This was first noticed by Shorey [14], and has been applied
in numerous works relating to (1) or to the Diophantine equationformula heresee for instance [1, 5, 10]. The purpose of the present work is to prove a similar
sharpening for linear forms in p-adic logarithms and to show how it can be applied
in the context of (1). Further, following previous investigations by Sander [12] and
Saradha & Shorey [13], we derive from our results an irrationality statement for
Mahler's numbers.