We give a simple criterion for the solvability in integers
of the negative Pell equation $x^2 - dy^2 = -1$ by means of
primitive Pythagorean triples. The method of proof allows us
to also solve the problem of determinig the fundamental units
of negative norm in real quadratic fields.
@article{1148393496,
author = {Grytczk, Aleksander and Luca, Florian and W\'ojtowicz, Marek},
title = {The negative Pell equation and Pythagorean triples},
journal = {Proc. Japan Acad. Ser. A Math. Sci.},
volume = {76},
number = {10},
year = {2000},
pages = { 91-94},
language = {en},
url = {http://dml.mathdoc.fr/item/1148393496}
}
Grytczk, Aleksander; Luca, Florian; Wójtowicz, Marek. The negative Pell equation and Pythagorean triples. Proc. Japan Acad. Ser. A Math. Sci., Tome 76 (2000) no. 10, pp. 91-94. http://gdmltest.u-ga.fr/item/1148393496/