One of the major interests of finite model theory is to separate the expressive power of different logics or fragments of logics. In this paper, we define a variant of EhrenfeuchtF...
A map is a graph equipped with a circular order of edges around each vertex. These circular orders represent local planar embeddings. The genus of a map is the minimal genus of an...
A residuated algebra (RA) is a generalization of a residuated groupoid; instead of one basic binary operation · with residual operations \, /, it admits finitely many basic oper...
A schema mapping is a specification that describes how data structured under one schema (the source schema) is to be transformed into data structured under a different schema (the...
Ronald Fagin, Phokion G. Kolaitis, Lucian Popa, Wa...