2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/184602We describe the twisted Yangians Y(g,h) which arise as boundary remnants of Yangians Y(g) in 1+1D integrable field theories. We describe and extend our recent construction of the intertwiners of their representations (the rational boundary S- or 'K'-matrices) and perform a case-by-case analysis for all pairs (g,h), giving the h-decomposition of Y(g,h)-representations where possible.16 pages. v3 has minor corrections and updates, and more detail on Casimir normalizationsQuantum AlgebraHigh Energy Physics - Theorytext