We give a simple proof of the Siegel-Tatuzawa theorem according to which the residues at s = 1 of the Dedekind zeta functions of quadratic number fields are effectively not too small, with at most one exceptional quadratic field. We then give a simple proof of the Brauer-Siegel theorem for normal number fields which gives the asymptotics for the logarithm of the product of the class number and the regulator of number fields.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-cm108-2-9, author = {St\'ephane R. Louboutin}, title = {Simple proofs of the Siegel-Tatuzawa and Brauer-Siegel theorems}, journal = {Colloquium Mathematicae}, volume = {107}, year = {2007}, pages = {277-283}, zbl = {1114.11090}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm108-2-9} }
Stéphane R. Louboutin. Simple proofs of the Siegel-Tatuzawa and Brauer-Siegel theorems. Colloquium Mathematicae, Tome 107 (2007) pp. 277-283. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm108-2-9/