We recall from [10] a Gδ σ-ideal of compact subsets of 2 ω and prove that it is not Tukey reducible to the ideal I1/n = {H ⊆ ω : ∑ h∈H 1/h <∞}. This result answers a question of S. Solecki and S. Todorčević in the negative.

Hongliang Cai, Nghia Nguyen, Vincent Peterkin, Young-Sun Yang, Kathy Hotz, Deirdre Beaton La Placa, Shujuan Chen, Robert H. Tukey, and Jeffrey C. Stevens Department of Pharmacokinetics, Dynamics, and Metabolism, St Louis Laboratories, PGRD, Chesterfield, MO 63017 (H.C., V.P., Y-S.Y., K.H., J.C.S.); Laboratory of Environmental Toxicology, Departments of Chemistry & Biochemistry and Pharmacology,...

The sunspot number time series was used to examine different methods of the periodogram as a spectrum estimator. The periodogram was used as the benchmark to compare the results of the sunspot cycle period estimate to the modified periodogram, the Blackman-Tukey method of periodogram smoothing, the Welch-Bartlett method of periodogram averaging and the Multitaper method. The Welch-Bartlett meth...

In this work we derive two families of radix-4 factorizations for the FFT (Fast Fourier Transform) that have the property that both inputs and outputs are addressed in natural order. These factorizations are obtained from another two families of radix-2 algorithms that have the same property. The radix-4 algorithms obtained have the same mathematical complexity (number of multiplications and ad...

We introduce a new construct that can be used to parametrize a topological Ramsey space by the collection of infinite subsets of natural numbers. We show that these parametrized spaces are topological Ramsey spaces. Then we prove a canonical Ramsey theorem for some of the parametrized spaces arising from the construction and conclude with some open questions concerning applications of these can...