Suppose \(\mathbb{K}\) is either \(\mathbb{R}\) or \(\mathbb{C}\) and \(p\in (0,\infty)\). The weak \(l^p\)-norm is a quasinorm . [1, Lemma 1.10]

References Link to heading

1. I. Veselic. Class Lecture, Topic: Compressive Sensing. Technische Universität Dortmund, 2017.