Applying results on linear forms in p-adic logarithms, we prove that if (x,y,z) is a positive integer solution to the equation with gcd(x,y) = 1 then (x,y,z) = (2,1,k), (3,2,k), k ≥ 1 if c = 1, and either , k ≥ 1 or if c ≥ 2.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-cm128-2-13, author = {Zhongfeng Zhang and Jiagui Luo and Pingzhi Yuan}, title = {On the diophantine equation $x^y - y^x = c^z$ }, journal = {Colloquium Mathematicae}, volume = {126}, year = {2012}, pages = {277-285}, zbl = {1297.11017}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm128-2-13} }
Zhongfeng Zhang; Jiagui Luo; Pingzhi Yuan. On the diophantine equation $x^y - y^x = c^z$ . Colloquium Mathematicae, Tome 126 (2012) pp. 277-285. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm128-2-13/