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The Simulated Greedy Algorithm for Several Submodular Matroid Secretary Problems Ma, Tengyu Tang, Bo Wang, Yajun secretary problem submodular function matroid online algorithm We study the matroid secretary problems with submodular valuation functions. In these problems, the elements arrive in random order. When one element arrives, we have to make an immediate and irrevocable decision on whether to accept it or not. The set of accepted elements must form an independent set in a predefined matroid. Our objective is to maximize the value of the accepted elements. In this paper, we focus on the case that the valuation function is a non-negative and monotonically non-decreasing submodular function. We introduce a general algorithm for such submodular matroid secretary problems. In particular, we obtain constant competitive algorithms for the cases of laminar matroids and transversal matroids. Our algorithms can be further applied to any independent set system defined by the intersection of a constant number of laminar matroids, while still achieving constant competitive ratios. Notice that laminar matroids generalize uniform matroids and partition matroids. On the other hand, when the underlying valuation function is linear, our algorithm achieves a competitive ratio of 9.6 for laminar matroids, which significantly improves the previous result. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Tengyu Ma and Bo Tang and Yajun Wang 2013 Is Part Of LIPIcs, Volume 20, 30th International Symposium on Theoretical Aspects of Computer Science (STACS 2013) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.STACS.2013.478 urn:nbn:de:0030-drops-39586 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2013.478 eng https://creativecommons.org/licenses/by-nd/3.0/legalcode