SageManifolds metaticket 2

[egourgoulhon]

This metaticket collects tickets related to manifolds in Sage 9.3 or higher. For the initial implementation of manifolds in Sage up to version 9.2, see the metaticket 1: #18528.

The works listed here result from the ​SageManifolds project, developed by the following ​authors.

Generic

• #30139: Metaticket about manifold code improvement
• #30116: Replace __eq__ by _richcmp_ for manifolds
• #30473: Unicode art for sage.manifolds
• #30554: Metaticket: deprecated features
• #30189: Add examples to manifold catalog
• #30799: Add folder for manifold examples

Algebraic part

• #28813: Enhance symmetry handling for tensors
• #29099: Extension of admissible indices conventions for tensors with indices
• #29619: Sparse iterator for tensor components
• #29820: Compacting the display of tensor product
• #29796: Parallelization of wedge product
• #30095: sage.tensor.modules: Add SymPowerFreeModule
• #30096: sage.tensor.modules: Add backends using TensorFlow Core and PyTorch:
• #30164: Add category FreeModules (without distinguished basis)
• #30174: Trivial coercion Modules(QQ)(FiniteRankFreeModule(QQ, 3)) fails
• #30229: Submodules of TensorFreeModule defined by the symmetries of a Components object
• #30235: Add construction methods to FiniteRankFreeModule and CombinatorialFreeModule
• #30241: New implementation class FiniteRankDualFreeModule
• #30242: Make ExtPowerFreeModule a quotient of TensorFreeModule
• #30245: FreeModuleAutomorphism should not inherit from FreeModuleTensor
• #30244: Use _matmul_ operator (@)
• #30276: Phased permutation groups
• #30302: Arithmetic on tensor module elements, manifold objects: always return a copy

Topological manifolds

• #24151: Improve simplifications in calculus on manifolds
• #24290: Make simplifications in SymPy calculus on manifolds rely on SymPy only
• #29775: Add a bit of typing to manifold code
• #30232: Coercion/conversion SR to ScalarFieldAlgebra
• #30263: declare_union yields wrong results
• #30310: Immutability of chart functions

Differentiable manifolds

• #28629: Automorphism fields: remove SR enforcement when computing the inverse
• #28640: Vector-valued forms:
• #27492: Bug in parallelized computations involving symbolic functions
• #29234: Inheritance structure: tensor fields as sections of vector bundles
• #29581: New algorithm for characteristic classes
• #30211: Characteristic classes: sequences
• #30261: Immutability for manifold objects
• #30272: Mixed forms: set_comp, comp
• #30495: sage.manifolds: Connect to Pymanopt
• #30714: Tensor arithmetics on minimal amount of domains
• #30781: Covariant derivatives along smooth maps

Pseudo-Riemannian manifolds

• #25457: Declaring a metric along with its components
• #25500: Energy momentum tensor, Einstein tensor and Einstein space-time
• #30804: Add standard sphere to manifold catalog

Poisson manifolds

• #30362: Add symplectic structures

Complex and almost complex manifolds

• #18786: almost complex structures through Hodge structures