Time-free solution to independent set problem using P systems with active membranes

Membrane computing is a branch of natural computingwhich abstracts fromthestructure and the functioning of living cells. The computation models obtainedin the field of membrane computing are usually called P systems. P systems havebeen used to solve computationally hard problems efficiently on the assumptionthat the execution of each rule is completed in exactly one time-unit (a globalclock is assumed for timing and synchronizing the execution of rules). However,in biological reality, different biological processes take different times tobe completed, which can also be influenced by many environmental factors. Inthis work, with this biological reality, we give a time-free solution toindependent set problemusing P systems with active membranes, which solve theproblem independent of the execution time of the involved rules