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arXiv · 1907.04696

Quotients of groups of birational transformations of cubic Del Pezzo fibrations

Jérémy Blanc·Egor Yasinsky
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Abstract

We prove that the group of birational transformations of a Del Pezzo fibration of degree 3 over a curve is not simple, by giving a surjective group homomorphism to a free product of infinitely many groups of order 2. As a consequence we also obtain that the Cremona group of rank 3 is not generated by birational maps preserving a rational fibration. Besides, its subgroup generated by all connected algebraic subgroups is a proper normal subgroup.

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Jérémy Blanc, Egor Yasinsky. 2019-07-10. Quotients of groups of birational transformations of cubic Del Pezzo fibrations. https://arxiv.org/abs/1907.04696

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