Some remarks on the Krein--von Neumann extension of different Laplacians

We discuss the Krein--von Neumann extensions of three Laplacian-type operators -- on discrete graphs, quantum graphs, and domains. In passing we present a class of one-dimensional elliptic operators such that for any $n\in \mathbb N$ infinitely many elements of the class have $n$-dimensional null space.Comment: 13 page

On the Spectrum of Holonomy Algebras

Connections on a trivial bundle MxG can be identified with their holonomy maps, i.e. with homomorphisms of a groupoid of paths in M into the gauge group G. For a connected compact G, various algebras depending on the set of the smooth connections through their holonomy maps have been introduced in the literature, called cylindrical and holonomy algebras. We discuss the relations between these algebras and the consistence of their spectra.Comment: 23 pages, no figures, to appear in J.Geom.Phy