We show that the number of factorizations \_=/ 1 } } } / r of a cycle of length n into a product of cycles of lengths a 1 , ..., a r , with r j=1 (a j &1)=n&1, is equal to n r&1 . This generalizes a well known result of J. Denes, concerning factorizations into a product of transpositions. We investi
A note on the minimization of symmetric and general submodular functions
β Scribed by H Narayanan
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 131 KB
- Volume
- 131
- Category
- Article
- ISSN
- 0166-218X
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β¦ Synopsis
In this paper we relate the minimization problems for general submodular functions and symmetric submodular functions. We characterize the contractions and restrictions of symmetric submodular functions. The latter we show to be the same as posimodular functions. Finally, we prove the equivalence of various symmetric submodular function minimization problems and the general submodular function minimization problem. We also give a preprocessing algorithm for the general submodular function minimization problem which could lead to substantial size reduction.
π SIMILAR VOLUMES
We prove that a real symmetric polynomial inequality of degree d 2 holds on R n + if and only if it holds for elements with at most d/2 distinct non-zero components, which may have multiplicities. We establish this result by solving a Cauchy problem for ordinary differential equations involving the
Hanlon, P., A Markov chain on the symmetric group and Jack symmetric functions, Discrete Mathematics 99 (1992) 123-140. Diaconis and Shahshahani studied a Markov chain Wf(l) whose states are the elements of the symmetric group S,. In W,(l), you move from a permutation n to any permutation of the for