Ignora la copia: sobre el sincretismo parcial entre 'ser' e 'ir'
This article proposes a structural explanation of the fact that in the perfective form, the verb ser is identical to ir. It is argued that internally ir is built over the verb ser, and the element that distinguishes them semantically displaces to a high position, in such a way that the lower copy left behind it is ignored for the purposes of morphophonological materialisation. The analysis concentrates in the perfective forms, and from there it is extended to the subjunctive imperfective.
Published version, source at http://revistas.uca.es/index.php/pragma/article/view/2354