Abstract
Motivated by the inequality , Carbery (2009) raised the question of what is the “right” analogue of this estimate in for . Carlen, Frank, Ivanisvili and Lieb (2018) recently obtained an version of this inequality by providing upper bounds for in terms of the quantities , and when , and lower bounds when , thereby proving (and improving) the suggested possible inequalities of Carbery. We continue investigation in this direction by refining the estimates of Carlen, Frank, Ivanisvili and Lieb. We obtain upper bounds for also when and lower bounds when . For we extend our upper bounds to any finite number of functions. In addition, we show that all our upper and lower bounds of for , , are the best possible in terms of the quantities , and , and we characterize the equality cases.
Citation
Paata Ivanisvili. Connor Mooney. "Sharpening the triangle inequality: envelopes between $L^{2}$ and $L^{p}$ spaces." Anal. PDE 13 (5) 1591 - 1603, 2020. https://doi.org/10.2140/apde.2020.13.1591
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