This is the Z/Object-Z Queue specification. [MSG, T] max N max > 100 Queue items &seq; MSG #items ≤ max QueueInit Queue items = &emptyseq; Add Queue item? MSG items' = items &cat; &lseq;item?&rseq; Delete Queue item! MSG items &neq; &emptyseq; items =&lseq;item!&rseq; &cat; items' Penguin Add Delete Queue items &seq; MSG # items≤max items=&emptyseq; Add items item? MSG items'=items&cat;&lseq;item?&rseq; Delete items item! MSG items &neq; &emptyseq; items=&lseq;item!&rseq;&cat;items' ActiveQueue Queue Ti, Tj T in, out &chan; Join [item:MSG] | #items ≤ max] ˙in? items &tfun;Add ˙ DEADLINE Tj Leave [item &neq; &emptyseq;] ˙ out! head(items) &tfun; Detete ˙ DEADLINE Tl MAIN μQ ˙ Join &extchoice; Leave; Q TwoQueue q1, q2 Queue Join q1.Add Leave q2.Delete Transfer q1.Delete ∥ q2.Add TwoActiveQueue q1 ActiveQueue[talk/out] q2 ActiveQueue[talk/in] MAIN ∥ (q1 &netchl; talk &netchr; q2)