Abstract
We classify commutative algebraic monoid structures on normal affine surfaces over an algebraically closed field of characteristic zero.
The answer is given in two languages: comultiplications and Cox coordinates.
The result follows from a more general classification of commutative monoid structures of rank 0,
Funding source: Basis Foundation
Award Identifier / Grant number: 18-1-6-19-1
Funding statement: The work was supported by the Foundation for Advancement of Theoretical Physics and Mathematics βBASISβ.
Acknowledgements
The authors are grateful to their supervisor Ivan Arzhantsev for careful reading of the paper and valuable suggestions, to Juergen Hausen for useful comments and to the referee for proposed corrections and improvements.
Communicated by: Jan Frahm
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