PreprintCC BY-NC-ND 4.0HAL
Affine noncommutative geometry
Abstract
This is an introduction to noncommutative geometry, from an affine viewpoint, that is, by using coordinates. The spaces ℝN,ℂN have no free analogues in the operator algebra sense, but the corresponding unit spheres SN−1 R,SN−1 C do have free analogues SN−1ℝ,+,SN−1ℂ,+. There are many examples of real algebraic submanifolds X⊂ SN−1ℝ,+,SN−1ℂ,+, some of which are of Riemannian flavor, coming with a Haar integration functional ∫:C(X)→ℂ, that we will study here. We will mostly focus on free geometry, but we will discuss as well some related geometries, called easy, completing the picture formed by the 4 main geometries, namely real/complex, classical/free.
Related
- Noncommutative resolutions of affine Schubert varieties in type A and canonical bases
- Affine Left--Right Dirac Data on the Moyal Plane, with an Application to U(1)⋆ Gauge Coupling in Noncommutative Quantum Mechanics
- Dualisable categories in noncommutative geometry
- Derivation based noncommutative geometry of quiver path algebras
- Measure-free Koopman-von Neumann dynamics and noncommutative Geometry
BibTeX
@misc{banica2026affine,
title = {{Affine noncommutative geometry}},
author = {Teo Banica},
howpublished = {HAL},
year = {2026},
month = oct,
url = {https://hal.science/hal-03312800v7},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Affine noncommutative geometry
AU - Teo Banica
PY - 2026
DA - 2026/10/01
PB - HAL
UR - https://hal.science/hal-03312800v7
AB - This is an introduction to noncommutative geometry, from an affine viewpoint, that is, by using coordinates. The spaces ℝ^N,ℂ^N have no free analogues in the operator algebra sense, but the corresponding unit spheres S^N−1_ R,S^N−1_ C do have free analogues S^N−1_ℝ,+,S^N−1_ℂ,+. There are many examples of real algebraic submanifolds X⊂ S^N−1_ℝ,+,S^N−1_ℂ,+, some of which are of Riemannian flavor, coming with a Haar integration functional ∫:C(X)→ℂ, that we will study here. We will mostly focus on free geometry, but we will discuss as well some related geometries, called easy, completing the picture formed by the 4 main geometries, namely real/complex, classical/free.
ER -