%0 Journal Article %T The Diophantine Equation $x^4 + 2 y^4 = z^4 + 4 w^4$---a number of improvements %A Andreas-Stephan Elsenhans %A J£¿rg Jahnel %J Mathematics %D 2010 %I arXiv %X The quadruple $(1\,484\,801, 1\,203\,120, 1\,169\,407, 1\,157\,520)$ already known is essentially the only non-trivial solution of the Diophantine equation $x^4 + 2 y^4 = z^4 + 4 w^4$ for $|x|$, $|y|$, $|z|$, and $|w|$ up to one hundred million. We describe the algorithm we used in order to establish this result, thereby explaining a number of improvements to our original approach. %U http://arxiv.org/abs/1006.1196v1