From 6c3f6c966a718535af5a3dc16979b4d428aed83b Mon Sep 17 00:00:00 2001 From: Miguel Marco Date: Tue, 22 Oct 2024 18:47:44 +0200 Subject: [PATCH] Fix bug in covering map with degenerate faces. --- src/sage/categories/simplicial_sets.py | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/src/sage/categories/simplicial_sets.py b/src/sage/categories/simplicial_sets.py index aabd3cdbb4f..af0144085fa 100644 --- a/src/sage/categories/simplicial_sets.py +++ b/src/sage/categories/simplicial_sets.py @@ -484,7 +484,7 @@ def covering_map(self, character): char[s] = G.one() for d in range(1, self.dimension() + 1): - for s in self.n_cells(d): + for s in self.all_n_simplices(d): if s not in char.keys(): if d == 1 and s.is_degenerate(): char[s] = G.one() @@ -575,6 +575,16 @@ def universal_cover(self): (f * f * f, e): ((f * f, 1), s_0 (f, e), s_1 (f, e), (f * f, e))} sage: C.fundamental_group() Finitely presented group < | > + + TESTS:: + + sage: RP2 = simplicial_sets.RealProjectiveSpace(2) + sage: S3 = simplicial_sets.Sphere(3) + sage: X = S3.wedge(RP2) + sage: XU = X.universal_cover() + sage: [XU.homology(i) for i in range(5)] + [0, 0, Z, Z x Z, 0] + """ return self.universal_cover_map().domain()