Alhazov, ArtiomRogozhin, Yurii2016-02-252016-02-25200584-609-6771-9http://hdl.handle.net/11441/36534In this paper we consider symport/antiport P systems with one membrane and rules having at most two objects. Although it has been proved that only finite number sets can be generated by both OP1(sym2) (one-membrane systems with symport rules of weight at most 2) and OP1(sym1; anti1) (one-membrane systems with symport/antiport rules of weight 1), the exact characterization is still an open question. We give some lower bounds, consider a few extensions, and state some open questions.application/pdfengAttribution-NonCommercial-NoDerivatives 4.0 Internacionalhttp://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/conferenceObjectinfo:eu-repo/semantics/openAccess