%0 Journal Article
%T Uniform bounds for point cohomology of $\ell^1({\mathbb Z}_+)$ and related algebras
%A Yemon Choi
%J Mathematics
%D 2008
%I arXiv
%R 10.1016/j.jmaa.2009.05.002
%X It is well-known that the point cohomology of the convolution algebra $\ell^1({\mathbb Z}_+)$ vanishes in degrees 2 and above. We sharpen this result by obtaining splitting maps whose norms are bounded independently of the choice of point module. Our construction is a by-product of new estimates on projectivity constants of maximal ideals in $\ell^1({\mathbb Z}_+)$. Analogous results are obtained for some other $L^1$-algebras which arise from `rank one' subsemigroups of ${\mathbb R}_+$.
%U http://arxiv.org/abs/0808.2265v4