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In mathematics, Brown–Peterson cohomology is a generalized cohomology theory introduced by Edgar H. Brown and Franklin P. Peterson (1966), depending on a choice of prime p. It is described in detail by Douglas Ravenel (2003, Chapter 4). Its representing spectrum is denoted by BP.

Complex cobordism and Quillen's idempotent[edit]

Brown–Peterson cohomology BP is a summand of MU_(p), which is complex cobordism MU localized at a prime p. In fact MU_(p) is a wedge product of suspensions of BP.

For each prime p, Daniel Quillen showed there is a unique idempotent map of ring spectra ε from MUQ_(p) to itself, with the property that ε([CPⁿ]) is [CPⁿ] if n+1 is a power of p, and 0 otherwise. The spectrum BP is the image of this idempotent ε.

Structure of BP[edit]

The coefficient ring $\pi _{*}({\text{BP}})$ is a polynomial algebra over $\mathbb {Z} _{(p)}$ on generators $v_{n}$ in degrees $2(p^{n}-1)$ for $n\geq 1$ .

${\text{BP}}_{*}({\text{BP}})$ is isomorphic to the polynomial ring $\pi _{*}({\text{BP}})[t_{1},t_{2},\ldots ]$ over $\pi _{*}({\text{BP}})$ with generators $t_{i}$ in ${\text{BP}}_{2(p^{i}-1)}({\text{BP}})$ of degrees $2(p^{i}-1)$ .

The cohomology of the Hopf algebroid $(\pi _{*}({\text{BP}}),{\text{BP}}_{*}({\text{BP}}))$ is the initial term of the Adams–Novikov spectral sequence for calculating p-local homotopy groups of spheres.

BP is the universal example of a complex oriented cohomology theory whose associated formal group law is p-typical.

References[edit]

Adams, J. Frank (1974), Stable homotopy and generalised homology, University of Chicago Press, ISBN 978-0-226-00524-9
Brown, Edgar H. Jr.; Peterson, Franklin P. (1966), "A spectrum whose Z_p cohomology is the algebra of reduced p^th powers", Topology, 5 (2): 149–154, doi:10.1016/0040-9383(66)90015-2, MR 0192494.
Quillen, Daniel (1969), "On the formal group laws of unoriented and complex cobordism theory" (PDF), Bulletin of the American Mathematical Society, 75 (6): 1293–1298, doi:10.1090/S0002-9904-1969-12401-8, MR 0253350.
Ravenel, Douglas C. (2003), Complex cobordism and stable homotopy groups of spheres (2nd ed.), AMS Chelsea, ISBN 978-0-8218-2967-7
Wilson, W. Stephen (1982), Brown-Peterson homology: an introduction and sampler, CBMS Regional Conference Series in Mathematics, vol. 48, Washington, D.C.: Conference Board of the Mathematical Sciences, ISBN 978-0-8219-1699-5, MR 0655040

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Complex cobordism and Quillen's idempotent[edit]

Structure of BP[edit]

See also[edit]

References[edit]

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