We introduce Priority Channel Systems, a new class of channel systems where messages
carry a numeric priority and where higher-priority messages can supersede lower-priority
messages preceding them in the fifo communication buffers. The decidability of safety and
inevitability properties is shown via the introduction of a priority embedding, a well-quasi-
ordering that has not previously been used in well-structured systems. We then show how
Priority Channel Systems can compute Fast-Growing functions and prove that the …

… For a PCS with state set Q and m channels: transition system (Q×(Σ … For a PCS with
state set Q and m channels: transition system (Q×(Σ … model priority channel systems
ordering priority embedding …