2016/12/12 by Křepela, Martin
#46E30 #47G10 #FOS: Mathematics #Functional Analysis (math.FA)
paper · doi:10.48550/arxiv.1612.03725
Let m,p,q∈(0,∞) and let u,v,w be nonnegative weights. We characterize validity of the inequality (∫0^∞ w(t) (f^*(t))q dt )^\frac 1q ≤ C (∫0^∞ v(t) (∫t^∞ u(s) (f^*(s))m ds )^\frac pm dt )^\frac 1p for all measurable functions f defined on ℝn and provide equivalent estimates of the optimal constant C>0 in terms of the weights and exponents. The obtained conditions characterize the embedding of the Copson-Lorentz space CLm,p(u,v), generated by the functional ‖f‖_CLm,p(u,v) := (∫0^∞ v(t) (∫t^∞ u(s) (f^*(s))m ds )^\frac pm dt )^\frac 1p, into the Lorentz space Λq(w). Moreover, the results are applied to describe the associated space of the Copson-Lorentz space CLm,p(u,v) for the full range of exponents m,p∈(0,∞).