Stateless connectors 8 Semantics 6 Algebra 4 Algebraic properties 4 Component based systems 4 Different class 4 P/T net 4 Petri nets 4 Tile models 4 Basic algebra 2 C/E nets with boundaries 2 Calculations 2 Component framework 2 Compositional interfaces 2 Connector algebras 2 Coordinated system 2 Coordination language 2 Heterogeneous component 2 Individual components 2 Mathematical foundations 2 Middleware 2 Model checking 2 Mutual exclusions 2 P/T nets with boundaries 2 Software engineering 2 Surveys 2 Tile 2 Tiles 2