English

Convolutions with the continuous primitive integral

Classical Analysis and ODEs 2009-09-25 v1 Functional Analysis

Abstract

If FF is a continuous function on the real line and f=Ff=F' is its distributional derivative then the continuous primitive integral of distribution ff is abf=F(b)F(a)\int_a^bf=F(b)-F(a). This integral contains the Lebesgue, Henstock--Kurzweil and wide Denjoy integrals. Under the Alexiewicz norm the space of integrable distributions is a Banach space. We define the convolution fg(x)=\intinff(xy)g(y)dyf\ast g(x)=\intinf f(x-y)g(y) dy for ff an integrable distribution and gg a function of bounded variation or an L1L^1 function. Usual properties of convolutions are shown to hold: commutativity, associativity, commutation with translation. For gg of bounded variation, fgf\ast g is uniformly continuous and we have the estimate fgfg\bv\|f\ast g\|_\infty\leq \|f\|\|g\|_\bv where f=supIIf\|f\|=\sup_I|\int_If| is the Alexiewicz norm. This supremum is taken over all intervals IRI\subset\R. When gL1g\in L^1 the estimate is fgfg1\|f\ast g\|\leq \|f\|\|g\|_1. There are results on differentiation and integration of convolutions. A type of Fubini theorem is proved for the continuous primitive integral.

Keywords

Cite

@article{arxiv.0909.4336,
  title  = {Convolutions with the continuous primitive integral},
  author = {Erik Talvila},
  journal= {arXiv preprint arXiv:0909.4336},
  year   = {2009}
}
R2 v1 2026-06-21T13:49:48.509Z