Subsection [04X5]
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(2.4) Let be a point in and let be its reduction on (see [MN15, 2.2.2]). Let be the unique minimal stratum of that contains . By our assumption (2), is a log canonical center of . Then is a non-empty stratum of by the definition of a dlt pair. Thus, it determines a unique face of the dual intersection complex . Let be the prime components of that contain , and let be their multiplicities in . Then correspond precisely to the vertices of . We choose a positive integer such that is Cartier at the point for every , and we choose a local equation for at . Then is the point of the simplex with barycentric coordinates
with respect to the vertices . Under the embedding of into , the point corresponds to the monomial point represented by and the tuple
in the terminology of [MN15, 2.4.5]. It is obvious that this definition does not depend on the choices of and the local equations . It is also straightforward to check that is continuous, and that it is a retraction onto .