Changes between Version 28 and Version 31 of Ticket #26355


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Timestamp:
10/08/19 08:49:44 (2 years ago)
Author:
Dicolevrai
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  • Ticket #26355

    • Property Milestone changed from sage-8.9 to sage-9.0
    • Property Cc eric gourgoulhon added
    • Property Commit changed from e9f8bba07c03da6e45bec04df721c115f4063959 to 3a003dea55fe96685c7fe42ff03860211aea6c6b
  • Ticket #26355 – Description

    v28 v31  
    1414(See the book of Krishan L. Duggal and Aurel Bejancu in *REFERENCES*.)
    1515
    16 In the present module, you can definie any of the 4 types but most of the
    17 methods are implemented only for degenerate hypersurfaces who belong to
    18 `r-`lightlike submanifolds. However, their might be generalized to
    19 `1-`lightlike submanifolds. In the litterature there is a new approach
    20 (the rigging technique) for studying `1-`lightlike submanifolds but
    21 here we we the method of Krishan L. Duggal and Aurel Bejancu base on
     16In the present module, one can define any of the 4 types but most of the methods are implemented only for degenerate hypersurfaces who belong to
     17`r-`lightlike submanifolds. However, there might be generalized to
     18`1-`lightlike submanifolds. In the literature, there is a new approach (the rigging technique) for studying `1-`lightlike submanifolds but
     19here we the method of Krishan L. Duggal and Aurel Bejancu base on
    2220the screen distribution.
    2321
     
    4038
    4139Tensors on the ambient manifold `M` are projected on `H` along `N`
    42 to obtain induced objects. For instance, induced connection is the
    43 linear connexion defined on `H` through the Levi-Civitta connection of `g` along `N`.
     40to obtain induced objects. For instance, the induced connection is the linear connexion defined on `H` through the Levi-Civitta connection of `g` along `N`.
    4441
    45 To work on a degenerate submanifold, after defining `H` as an instance
    46 of :class:`~sage.manifolds.differentiable.manifold.DifferentiableManifold`,
    47 with the keyword *structure='degenerate_metric'*, you have to set a transvervector `v` and screen distribution together with the radical distribution.
     42To work on a degenerate submanifold, after defining `H` as an instance of :class:`~sage.manifolds.differentiable.manifold.DifferentiableManifold`, with the keyword *structure='degenerate_metric'*, you have to set a transvervector `v` and screen distribution together with the radical distribution.
    4843
    4944An example of degenerate submanifold from General Relativity is the