2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/74691We show that any n-vertex graph without even cycles of length at most 2k has at most 1/2(n^{1 + 1/k}) + O(n) edges, and polarity graphs of generalized polygons show that this is asymptotically tight when k = 2,3,5.6 pagesCombinatorics05C35; 05C38text