We review basic notions and methods of noncommutative geometry and their applications to analysis and geometry on foliated manifolds.

We introduce the linear connection in the noncommutative geometry model of the product of continuous manifold and the discrete space of two points. We discuss its metric properties, de ne the metric connection and calculate the curvature. We de ne also the Ricci tensor and the scalar curvature. We nd that the latter di ers from the standard scalar curvature of the manifold by a term, which migh...

An intersection of Noncommutative Geometry and Loop Quantum Gravity is proposed. Alain Connes’ Noncommutative Geometry provides a framework in which the Standard Model of particle physics coupled to general relativity is formulated as a unified, gravitational theory. However, to this day no quantization procedure compatible with this framework is known. In this paper we consider the noncommutat...

This paper is a brief account of the moduli of complex curves from the perspective of noncommutative geometry. We focus on problems of Riemann surface theory, which can be settled using K-groups of a noncommutative C∗-algebra. On this way, we prove “generic” arithmeticity of the mapping class group and study correspondences between complex and noncommutative tori.

A noncommutative algebra A, called an algebraic noncommutative geometry, is defined, with a parameter ε in the centre. When ε is set to zero, the commutative algebra A0 of algebraic functions on an algebraic manifold M is obtained. This A0 is a subalgebra of Cω(M), which is dense if M is compact. The generators of A define an immersion of M into Rn, and M inherits a Poisson structure as the lim...

We describe an algebraic approach to the time-dependent noncommutative geometry of a six-dimensional Cahen-Wallach pp-wave string background supported by a constant Neveu-Schwarz flux, and develop a general formalism to construct and analyse quantum field theories defined thereon. Various star-products are derived in closed explicit form and the Hopf algebra of twisted isometries of the plane w...

A short historical review is made of some recent literature in the field of noncommutative geometry, especially the efforts to add a gravitational field to noncommutative models of space-time and to use it as an ultraviolet regulator. An extensive bibliography has been added containing reference to recent review articles as well as to part of the original literature. LMU-TPW 99-11 ∗Lecure given...

The structure of spacetime duality and discrete worldsheet symmetries of compactified string theory is examined within the framework of noncommutative geometry. The full noncommutative string spacetime is constructed using the Fröhlich-Gawȩdzki spectral triple which incorporates the vertex operator algebra of the string theory. The duality group appears naturally as a subgroup of the automorphi...

This paper is a brief account of the moduli of complex curves from the perspective of noncommutative geometry. We focus on the uniformization of Riemann surfaces by the ordered K-groups of a noncommutative C-algebra. Using this approach, we prove “generic” arithmeticity of the mapping class group and study correspondences between complex and noncommutative tori.

Let n ≥ 2 and Tn be the space of n × n real skew-symmetric matrices. For each θ ∈ Tn the corresponding n-dimensional noncommutative torus Aθ is defined as the universal C-algebra generated by unitaries U1, · · · , Un satisfying the relation UkUj = e(θkj)UjUk, where e(t) = e. Noncommutative tori are one of the canonical examples in noncommutative differential geometry [12, 2]. One may also consi...