Romanian Academy Spatial Dynamic Structures and Mobility in Computation

Membrane computing is a well-established and successful research field which belongs to the more general area of molecular computing. Mem-brane computing aims at defining parallel and non-deterministic comput-ing models, called membrane systems or P Systems, which abstract from the functioning and structure of the cell. A membrane system consists of a spatial structure, a hierarchy of membranes which do not intersect, with a distinguishable membrane called skin surrounding all of them. A membrane without any other membranes inside is elementary, while a non-elementary membrane is a composite membrane. The membranes define demarcations between regions; for each membrane there is a unique asso-ciated region. Since we have a one-to-one correspondence, we sometimes use membrane instead of region, and vice-versa. The space outside the skin membrane is called the environment. In this thesis we define and investigate variants of systems of mo