2013/07/09 by Sebastian Zaigler, Domenico P. L. Castrigiano, Zaigler, Sebastian +1
Mathematics · #41A10 #47A16 #47B15 #FOS: Mathematics #Functional Analysis (math.FA) #math.FA #msc:41A10 #msc:47A16 #msc:47B15
paper · pdf · doi:10.48550/arxiv.1307.2437
10 pages, 0 figures
arxiv created 2013/07/09 · arxiv updated 2013/07/10
For every, possibly unbounded, multiplication operator in Lp-space, p∈ ]0,∞[, on finite separable measure space we show that multicyclicity, multi-*-cyclicity, and multiplicity coincide. This result includes and generalizes Bram's much cited theorem from 1955 on bounded *-cyclic normal operators. It also includes as a core result cyclicity of the multiplication operator Mz by the complex variable z in Lp(μ) for every Borel measure μ on \C. The concise proof is based in part on the result that the function e-|z|2 is a *-cyclic vector for Mz in C0(\C) and further in Lp(μ). We characterize topologically those locally compact sets X⊂ \C, for which Mz in C0(X) is cyclic.