Published online by Cambridge University Press: 18 February 2010
We find in the literature three distinct connections between combinatorial
isoperimetric problems and partially ordered sets:
The reduction of edge and vertex-isoperimetric problems on graphs (EIP and VIP) to maximum weight ideal (MWI) problems on the compressibility or stability order (see Chapters 3, 4, 5 and 6).
J. B. Kruskal's observation, in 1969 [66], that a graph may be looked upon as a two-dimensional complex and then its (incident) EIP has a natural extension to arbitrary complexes (hypergraphs). The extension is called the minimum shadow problem (MSP). Kruskal had already solved the MSP [65] for the simplex in all dimensions, a result discovered independently by G. O. H. Katona [58]. The Kruskal–Katona theorem is probably the most widely known and applied of all combinatorial isoperimetric theorems. Kruskal went on in [66] to conjecture that our solution of the EIP on Qd, the graph of the d-cube (see Chapters 1 and 3), could be extended to the MSP on the complex of faces of the d-cube. He also suggested looking for more such analogs of the Kruskal–Katona theorem.
Scheduling problems are standard fare in applied combinatorial optimization. If the steps of a manufacturing process must be carried out in some serial order subject to given precedence constraints, and we wish to order the steps so as to minimize some functional of the ordering, such as the average time between when a step is completed and its last successor is completed, then we have a scheduling problem.
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.