Unsolved Problem Q101001



Pillai's Conjecture


Statement:

The gaps in the sequence of perfect powers tend to infinity

~Equivalently~

Every positive integer occurs only finitely many times as a difference of perfect powers

~Generally~

For fixed positive integers \(A,B,C\), the equation \( Ax^n-By^m=C \) has only finitely many solutions \((x,y,m,n)\) for \((m,n)\neq (2,2)\)



Author  Date Published 
     
Subbayya Sivasankaranarayana Pillai  1931 


Partial Results:

Pillai proved [1] that the difference \( \left|Ax^n-bx^m\right|\ll x^{\lambda n} \) for \(\lambda<1\), uniformly in \(n\) and \(m\).

The general form of Pillai's Conjecture would follow from the ABC conjecture. [1] [2]



Related Problems:


References:

[1] Narkiewicz, Wladyslaw (2011), Rational Number Theory in the 20th Century: From PNT to FLT, Springer Monographs in Mathematics, Springer-Verlag, pp. 253–254, ISBN 978-0-857-29531-6


[2] Schmidt, Wolfgang M. (1996), Diophantine approximations and Diophantine equations, Lecture Notes in Mathematics, 1467 (2nd ed.), Springer-Verlag, p. 207, ISBN 3-540-54058-X, Zbl 0754.11020



Keywords:

difference of perfect powers;