Modules in Monoidal Model Categories

This paper studies the existence of and compatibility between derived change of ring, balanced product, and function module derived functors on module categories in monoidal model categories

The Multiplication on BP

BP is an E_4 ring spectrum. The E_4 structure is unique up to automorphism

The strong K\"unneth theorem for topological periodic cyclic homology

Topological periodic cyclic homology (i.e., $\mathbb{T}$-Tate of $THH$) has the structure of a strong symmetric monoidal functor of smooth and proper dg categories over a perfect field of finite characteristic

A Comparison of CDMA and Frequency Hopping in a Cellular Environment

This paper compares the performances of direct sequence code division multiple access (CDMA) and frequency hopping (FH) schemes in a cellular multiuser environment. The multiuser channel model incorporates the effects of propagation, frequency selective fading, and interference among users in the presence of a constrained system bandwidth. This channel model is applicable for cellular mobile communications, as well as other forms of personal communications. The CDMA and FH systems are compared using BPSK modulation. The main point of contrast between these systems is that the orthogonal hopping patterns in a FH system result in a decreased additive interference power, however the frequency spreading nature of CDMA results in the ability to combat fading. An information theoretic analysis is presented, which shows that system capacities are far above the performances achieved using simple coding scheme

Algebraic K-theory and abstract homotopy theory

We decompose the K-theory space of a Waldhausen category in terms of its Dwyer-Kan simplicial localization. This leads to a criterion for functors to induce equivalences of K-theory spectra that generalizes and explains many of the criteria appearing in the literature. We show that under mild hypotheses, a weakly exact functor that induces an equivalence of homotopy categories induces an equivalence of K-theory spectra.Comment: Final versio