2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/174620It is shown that the compressed word problem for an HNN-extension with base group H and finite associated subgroups is polynomial time Turing-reducible to the compressed word problem for H. An analogous result for amalgamated free products is shown as well.Group Theory20F10; 68Q17text