Người báo cáo: Nguyễn Hoàng Thạch
Thời gian: 9h30, Thứ 5, ngày 21 tháng 1, năm 2016 Địa điểm: Phòng 201, Nhà A5, Viện Toán học, 18 Hoàng Quốc Việt Cầu Giấy Hà Nội Tóm tắt: In the first part, we give the characterisation of a class of product-form Petri nets. We introduce the class of Pi2-nets for which a product-form steady-state distribution exists for every choice of transition rates. Next, we show that intersecting this class and the class of free-choice nets yields a classical class of product-form queueing networks: the Jackson networks. The second part consists of two effective methods to construct arbitrary Pi2-nets. One can either generate a Pi2-net from the empty net using a finite set of synthesising rules, or to directly modify an existing net. The third part gives a characterisation of the Pi2-nets in term of complexity. We show that the reachability and liveness problems are PSPACE-complete for 1-bounded Pi2-nets and that the coverability problem is EXPSPACE-complete for general Pi2-nets. Finally, we introduce the subclass of Pi3-nets whose normalising constant can be efficiently computed using dynamic programming.
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