2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/173674In this paper, we give a novel abstract description of Szabo's polycategories. We use the theory of double clubs -- a generalisation of Kelly's theory of clubs to `pseudo' (or `weak') double categories -- to construct a pseudo-distributive law of the free symmetric strict monoidal category pseudocomonad on Mod over itself qua pseudomonad, and show that monads in the `two-sided Kleisli bicategory' of this pseudo-distributive law are precisely symmetric polycategories.51 pages with XYpic diagrams; v2: journal version, improvements to Sections 2.2 and 3.2, other minor infelicities corrected; v3: missing appendix reinstatedCategory Theory18D05, 03G30 (Primary); 18D50, 03B60 (Secondary)text