Proc. Japan Acad. Ser. A Math. Sci. 80 (10), 191-193, (Dec. 2004) DOI: 10.3792/pjaa.80.191
Julius M. Basilla, Hideo Wada
KEYWORDS: Ternary quadrartic form, quadratic field, ideal class group, 2-part, 11E20, 11R29, 11R11, 11Y16
We shall show a relation between Gauss' ternary quadratic form and an ideal of a quadratic field. Using this relation, we can compute rapidly the 2-part of ideal class group of a quadratic field in narrow sense and in wide sense.