Amenability for discrete convolution semigroup algebras.
The genus problem for one-relator products of locally indicable groups.
On Zariski-regularity, the vanishing of Tor and a uniform Artin-Rees theorem
The Area and the Side I Added: Some old Babylonian Geometry
There was a standard procedure in Mesopotamia for solving quadratic problems involving lengths and areas of squares. In this paper, we show, by means of an example from Susa, how area constants were used to reduce problems involving other geometrical figures to the standard form.
Hermitian powers: A Müntz theorem and extremal algebras
Given ⊂ ℕ, let ̂ be the set of all positive integers m for which is hermitian whenever h is an element of a complex unital Banach algebra A with hⁿ hermitian for each n ∈ . We attempt to characterize when (i) ̂ = ℕ, or (ii) ̂ = . A key tool is a Müntz-type theorem which gives remarkable conclusions when 1 ∈ and ∑ 1/n: n ∈ diverges. The set ̂ is determined by a single extremal Banach algebra Ea(). We describe this extremal algebra for various .
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