2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/61991Let H be a separable infinite dimensional complex Hilbert space. We prove that every continuous 2-local automorphism of the poset (that is, partially ordered set) of all idempotents on H is an automorphism. Similar results concerning the orthomodular poset of all projections and the Jordan ring of all selfadjoint operators on H without the assumption on continuity are also presented.10 pages. To appear in Lett. Math. PhysOperator AlgebrasMathematical Physics47B49; 03G12text