Complex sentence: Full function PDF specification means that it is not only a subset of Adobe's PDF specification and in the case of ISO 32000-1 the full function PDF includes the whole functionality defined in Adobe's PDF 1.7 specification.
Split into simpler sentences: Full function PDF specification means that it is not only a subset of Adobe's PDF specification. In the case of ISO 32000-1 the full function PDF includes the whole functionality defined in Adobe's PDF 1.7 specification.