@article {2088, title = {Limits on Efficient Computation in P Systems with Symport/Antiport}, journal = {Fifteenth Brainstorming Week on Membrane Computing (BWMC2017)}, year = {2017}, pages = {147-160}, publisher = {F{\'e}nix Editora}, url = {http://www.gcn.us.es/15bwmc_proceedings}, author = {Luis F. Mac{\'\i}as-Ramos and Bosheng Song and Tao Song and Linqiang Pan and Mario J. P{\'e}rez-Jim{\'e}nez} }