Let A be a commutative algebra without zero divisors over a field k. If A is finitely generated over k, then there exist well known characterizations of all k-subalgebras of A which are rings of constants with respect to k-derivations of A. We show that these characterizations are not valid in the case when the algebra A is not finitely generated over k.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-cm99-1-5,
author = {Piotr J\k edrzejewicz},
title = {A note on characterizations of rings of constants with respect to derivations},
journal = {Colloquium Mathematicae},
volume = {100},
year = {2004},
pages = {51-53},
zbl = {1075.13504},
language = {en},
url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm99-1-5}
}
Piotr Jędrzejewicz. A note on characterizations of rings of constants with respect to derivations. Colloquium Mathematicae, Tome 100 (2004) pp. 51-53. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm99-1-5/