The elementary theory of ⟨α;×⟩, where α is an ordinal and × denotes ordinal multiplication, is decidable if and only if . Moreover if and respectively denote the right- and left-hand divisibility relation, we show that Th and Th are decidable for every ordinal ξ. Further related definability results are also presented.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-fm171-3-1, author = {Alexis B\`es}, title = {Decidability and definability results related to the elementary theory of ordinal multiplication}, journal = {Fundamenta Mathematicae}, volume = {173}, year = {2002}, pages = {197-211}, zbl = {0998.03005}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm171-3-1} }
Alexis Bès. Decidability and definability results related to the elementary theory of ordinal multiplication. Fundamenta Mathematicae, Tome 173 (2002) pp. 197-211. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm171-3-1/