The notion of quasi-periodic functions was generalised still further by Harald Bohr when he introduced almost-periodic functions.
Piers Morgan | Piers Plowman | Piers Anthony | Piers Sellers | Piers Gaveston | Chelsea Piers | Piers Maxwell Dudley-Bateman | Piers Gough | Piers Gaveston, 1st Earl of Cornwall | Piers Benn | Ryan Piers Williams | Piers Vitebsky | Piers Paul Read | Piers Morgan Live | Piers Flint-Shipman | Piers FitzThomas Butler | Piers Faccini | Piers Courage | Piers Butler, 8th Earl of Ormond | Langland's Dreamer: from an illuminated initial in a ''Piers Plowman | James Piers St Aubyn | Harbours, Docks and Piers Clauses Act 1847 |