Applications of the Weyl-Wigner formalism to noncommutative geometry

In this dissertation the Weyl-Wigner approach is presented as a map between functions on a real cartesian symplectic vector space and a set of operators on a Hilbert space, to analyse some aspects of the relations between quantum and classical formalism, both as a quantization, and as a classical limit. It is presented an extension of this formalism to the case of a more general classical phase space, namely one whose configuration space is a compact simple Lie group. In the second part, it is used to develop a fuzzy approximation to the algebra of functions on a disc. This is the first example of a fuzzy space originating from a classical space which has a boundary. It is analysed how this approximation copes the presence of ultraviolet divergences even in noninteracting field theories on a disc.