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Start Over Subject fibration

1. Orbit projections as fibrations

Creator:
Rainer, Armin
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
orbit projection, proper $G$-manifold, fibration, and quasifibration
Language:
English
Description:
The orbit projection $\pi \: M \to M/G$ of a proper $G$-manifold $M$ is a fibration if and only if all points in $M$ are regular. Under additional assumptions we show that $\pi $ is a quasifibration if and only if all points are regular. We get a full answer in the equivariant category: $\pi $ is a $G$-quasifibration if and only if all points are regular.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2. 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