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On the Swan conductor in positive characteristic
- American Journal of Mathematics
- Johns Hopkins University Press
- Volume 119, Number 4, August 1997
- pp. 705-739
- 10.1353/ajm.1997.0026
- Article
- Additional Information
Let X be a proper smooth surface over an algebraically closed field of positive characteristic and U be a complement of a simple normal crossing divisor. For a smooth l-adic sheaf Ƒ on U, Deligne proved a formula calculating the Euler characteristic of Ƒ by local invariants. Kato gave another formula for the Euler characteristic in case where Ƒ is of rank 1, using class field theory. In this paper, we show that local terms of these formulas coincide, admitting certain conjectures for vanishing cycles.