The maximal unipotent finite quotient, unusual torsion in Fano threefolds, and exceptional Enriques surfaces

The maximal unipotent finite quotient, unusual torsion in Fano threefolds, and exceptional Enriques surfaces

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We introduce and study the maximal unipotent finite quotient for algebraic group schemes in positive characteristics.Applied to Picard craggy range sauvignon blanc 2022 schemes, this quotient encodes unusual torsion.We construct integral Fano threefolds where such unusual torsion actually appears.The existence of such threefolds kt196 torque converter is surprising, because the torsion vanishes for del Pezzo surfaces.

Our construction relies on the theory of exceptional Enriques surfaces, as developed by Ekedahl and Shepherd-Barron.