Stephen B. Maurer

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There are two main objectives regarding tissue engineering in reconstructive urology: (1) to provide the surgeon with autologous tissue for urogenital reconstructive purposes and (2) to create the framework for experimental investigations to better understand the structure and function of the tissues involved. In the last years urothelial cell culture has(More)
An interval in a graph is a JL tigraph induced 1) f all tire vertices an shortest paths between two given vertices. Intervals in matroid basis gr lphs satisfy many nice properties. Key recsults are: (1) any two vertices of a k :~is g~~aph i,re together in some longest interval; (2) every basis graph with :he minimum number of vertaces for its diametex is an(More)
A combinatorial pregeometry, or matroid, may be defined as a finite set of elements E and a collection of bases M, all subsets of E, such that for all B,B' G âiï and any é eB' — £, there exists e e B — B' for which B — e + e' e&. This exchange axiom suggests it is fruitful to represent a pregeometry Jt by a graph : Let there be a vertex for each basis and(More)
The size of a minimum realizer of a partial order is called the dimension of that partial order. Here we initiate the study of minimal realizers which are not minimum. As an aid to the study of such realizers, we associate to each minimal realizer certain critical digraphs. We characterize all such critical digraphs for the antichain on n elements, and(More)
In a labor market hierarchy, promotions are affected by the noisiness of information about the candidates. I study the hypothesis that males are more risk taking than females, and its implications for rates of promotion and abilities of survivors. I define promotion hierarchies with and without memory, where memory means that promotion depends on the entire(More)