Let k = Fp be the field with p > 0 elements, and let G be a finite group. By exhibiting an E∞–operad action on Hom(P,k) for a complete projective resolution P of the trivial kG–module k, we obtain power operations of Dyer–Lashof type on Tate cohomology Ĥ∗(G;k). Our operations agree with the usual Steenrod operations on ordinary cohomology H∗(G). We show that they are compatible (in a suitable sense) with products of groups, and (in certain cases) with the Evens norm map. These theorems provide tools for explicit computations of the operations for small groups G. We also show that the operations in negative degree are nontrivial.
As an application, we prove that at the prime 2 these operations can be used to determine whether a Tate cohomology class is productive (in the sense of Carlson) or not.
Keywords: Tate cohomology, Dyer–Lashof, cohomology operation, finite group
Langer, Martin  1
@article{10_2140_agt_2012_12_829,
author = {Langer, Martin},
title = {Dyer{\textendash}Lashof operations on {Tate} cohomology of finite groups},
journal = {Algebraic and Geometric Topology},
pages = {829--865},
year = {2012},
volume = {12},
number = {2},
doi = {10.2140/agt.2012.12.829},
url = {http://geodesic.mathdoc.fr/articles/10.2140/agt.2012.12.829/}
}
TY - JOUR AU - Langer, Martin TI - Dyer–Lashof operations on Tate cohomology of finite groups JO - Algebraic and Geometric Topology PY - 2012 SP - 829 EP - 865 VL - 12 IS - 2 UR - http://geodesic.mathdoc.fr/articles/10.2140/agt.2012.12.829/ DO - 10.2140/agt.2012.12.829 ID - 10_2140_agt_2012_12_829 ER -
Langer, Martin. Dyer–Lashof operations on Tate cohomology of finite groups. Algebraic and Geometric Topology, Tome 12 (2012) no. 2, pp. 829-865. doi: 10.2140/agt.2012.12.829
[1] , Representations and cohomology, II : Cohomology of groups and modules, 31, Cambridge Univ. Press (1998)
[2] , , Products in negative cohomology, J. Pure Appl. Algebra 82 (1992) 107
[3] , , The action of the Steenrod algebra on Tate cohomology, J. Pure Appl. Algebra 85 (1993) 21
[4] , Products and projective resolutions, from: "The Arcata Conference on Representations of Finite Groups (Arcata, CA, 1986)" (editor P Fong), Proc. Sympos. Pure Math. 47, Amer. Math. Soc. (1987) 399
[5] , Modules and group algebras, , Birkhäuser (1996)
[6] , , Homological algebra, , Princeton Univ. Press (1999)
[7] , , , The homology of iterated loop spaces, 533, Springer (1976)
[8] , Steenrod operations and transfer, Proc. Amer. Math. Soc. 19 (1968) 1387
[9] , Representing Tate cohomology of G–spaces, Proc. Edinburgh Math. Soc. 30 (1987) 435
[10] , , Generalized Tate cohomology, 113, no. 543, Amer. Math. Soc. (1995)
[11] , The stable derived category of a Noetherian scheme, Compos. Math. 141 (2005) 1128
[12] , , Operads, algebras, modules and motives, 233, Soc. Math. France (1995)
[13] , , , , Equivariant stable homotopy theory, 1213, Springer (1986)
[14] , E∞ algebras and p–adic homotopy theory, Topology 40 (2001) 43
[15] , A general algebraic approach to Steenrod operations, from: "The Steenrod Algebra and its Applications (Proc. Conf. to Celebrate N E Steenrod’s Sixtieth Birthday, Battelle Memorial Inst., Columbus, OH, 1970)" (editor F P Peterson), Lecture Notes in Math. 168, Springer (1970) 153
[16] , E∞–ring structures for Tate spectra, Proc. Amer. Math. Soc. 124 (1996) 1917
[17] , Productive elements in group cohomology, Homology Homotopy Appl. 13 (2011) 381
Cité par Sources :