Volume 13, Issue 3 Włodzimierz Fechner Functional characterization of a sharpening of the triangle inequality Downloads Abstract PDF Full article PDF DOI { copied = true; setTimeout(() => copied = false, 2000) })" :aria-label="copied ? 'DOI copied' : 'Copy DOI'" :title="copied ? 'Copied' : 'Copy DOI'" > Find all available articles from these authors Włodzimierz Fechner Find more articles with the same keywords norm inequality triangle inequality functional equation functional inequality Hyers-Ulam stability Find more articles with the same subject classes 39B62 39B82 46B20 46B99