product product p q r p+q+r Create order product product product product order order order order Request bid order supplier (order, supplier) Send bid Time out order order order supplier (order,supplier) order supplier (order,supplier) order supplier (order,supplier) Select best bid order order order supplier (order, supplier) Deliver order supplier (order,supplier) order supplier (order,supplier) max concurrent orders order order supplier supplier s t v s+t+v supplier supplier supplier supplier order 2order order 2order order order order order order order order order produces relation supplier product (supplier, product) s p s q t p t r v r (s,p)+(s,q)+(t,p)+(t,r)+(v,r) supplier supplier supplier supplier