(2018) Letters in Mathematical Physics : a journal for the rapid dissemination of short contributions in the field of mathematical physics — Vol. 108, n° 5, p. 1341-1350 (2017)
In this short note, we point out that not every star product is induced by a Drinfel’d twist by showing that not every Poisson structure is induced by a classical r-matrix. Examples include the higher genus symplectic Pretzel surfaces and the symplectic sphere S2.
Bieliavsky, P., Esposito, C., Waldmann, S., & Weber, T. (2018). Obstructions for twist star products. Letters in Mathematical Physics : a journal for the rapid dissemination of short contributions in the field of mathematical physics, 108(5), 1341-1350. https://doi.org/10.1007/s11005-017-1034-z (Original work published 2017)