3,475 research outputs found
Multiplicative structures on homotopy spectral sequences I
This mostly expository paper records some basic facts about towers of
homotopy fiber sequences. We give a proof that a pairing of towers induces a
pairing of associated spectral sequences, for towers of spaces and towers of
spectra
A curious example of two model categories and some associated differential graded algebras
The paper gives a new proof that the model categories of stable modules for
the rings Z/(p^2) and (Z/p)[\epsilon]/(\epsilon^2) are not Quillen equivalent.
The proof uses homotopy endomorphism ring spectra. Our considerations lead to
an example of two differential graded algebras which are derived equivalent but
whose associated model categories of modules are not Quillen equivalent. As a
bonus, we also obtain derived equivalent dgas with non-isomorphic K-theories
Enriched model categories and an application to additive endomorphism spectra
We define the notion of an additive model category, and we prove that any
additive, stable, combinatorial model category has a natural enrichment over
symmetric spectra based on simplicial abelian groups. As a consequence, every
object in such a model category has a naturally associated endomorphism ring
inside this spectra category. We establish the basic properties of this
enrichment.
We also develop some enriched model category theory. In particular, we have a
notion of an adjoint pair of functors being a 'module' over another such pair.
Such things are called "adjoint modules". We develop the general theory of
these, and use them to prove a result about transporting enrichments over one
symmetric monoidal model category to a Quillen equivalent one.Comment: Sections completely re-organized from previous version. Mathematical
content all the sam
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S=0 pseudoscalar meson photoproduction from the proton
Many measurements of pseudoscalar mesons with S = 0 photoproduced on the
proton have been made recently. These new data are particularly useful in
theoretical investigations of nucleon resonances. How the new data from various
labs complement each other and help fill in the gaps in the world data set is
disscussed, with a glance at measurements to be made in the near future. Some
theoretical techniques used to explain the data are briefly described.Comment: 6 pages, 3 figures, Nstar workshop proceeding to be published with
World Scientifi
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