1. Orbit projections of proper Lie groupoids as fibrations Creator: Rainer, Armin Format: bez média and svazek Type: model:article and TEXT Subject: orbit projection, proper Lie groupoid, and fibration Language: English Description: Let $\mathcal{G} \rightrightarrows M$ be a source locally trivial proper Lie groupoid such that each orbit is of finite type. The orbit projection $M \to M/\mathcal{G}$ is a fibration if and only if $\mathcal{G}\rightrightarrows M$ is regular. Rights: http://creativecommons.org/publicdomain/mark/1.0/ and policy:public