Open AccessA note on the Diophantine equation $|a^x-b^y|=c$
Author(s) -
Bing He,
Alain Togbé,
Shichun Yang
Publication year - 2010
Publication title -
mathematica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.553
H-Index - 30
eISSN - 1903-1807
pISSN - 0025-5521
DOI - 10.7146/math.scand.a-15149
Subject(s) - diophantine equation , integer (computer science) , mathematics , exponential function , combinatorics , discrete mathematics , mathematical analysis , computer science , programming language
Let $a,b,$ and $c$ be positive integers. We show that if $(a,b) =(N^k-1,N)$, where $N,k\geq 2$, then there is at most one positive integer solution $(x,y)$ to the exponential Diophantine equation $|a^x-b^y|=c$, unless $(N,k)=(2,2)$. Combining this with results of Bennett [3] and the first author [6], we stated all cases for which the equation $|(N^k \pm 1)^x - N^y|=c$ has more than one positive integer solutions $(x,y)$.