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author | Viktor Kleen <viktor@kleen.org> | 2015-03-06 20:56:31 +0000 |
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committer | Viktor Kleen <viktor@kleen.org> | 2015-03-06 20:56:31 +0000 |
commit | 0303c4e1a700f6c5617f505a56cae88673a869da (patch) | |
tree | 4f13d7b233fb280e04e7b0c77f89f641e1f85759 | |
parent | 94956f26a68f129a4d4076ad83498d38629ad609 (diff) | |
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more torsors
l--------- | lists/torsors/001 | 1 | ||||
-rw-r--r-- | lists/torsors/title | 1 | ||||
-rw-r--r-- | posts/torsors.md | 2 |
3 files changed, 3 insertions, 1 deletions
diff --git a/lists/torsors/001 b/lists/torsors/001 new file mode 120000 index 0000000..69340df --- /dev/null +++ b/lists/torsors/001 | |||
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../../posts/torsors.md \ No newline at end of file | |||
diff --git a/lists/torsors/title b/lists/torsors/title new file mode 100644 index 0000000..3597b97 --- /dev/null +++ b/lists/torsors/title | |||
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Torsor in Toposes | |||
diff --git a/posts/torsors.md b/posts/torsors.md index b87c2df..a4cab97 100644 --- a/posts/torsors.md +++ b/posts/torsors.md | |||
@@ -94,7 +94,7 @@ and transitive, so in $\ca C/U$ we have the isomorphism | |||
94 | $$(G\times U)\times_U (X\times U) \iso (X\times U) | 94 | $$(G\times U)\times_U (X\times U) \iso (X\times U) |
95 | \times_U (X\times U)$$ | 95 | \times_U (X\times U)$$ |
96 | and $(G\times U)\times_U(X\times U) = (G\times X)\times U$ and $(X\times | 96 | and $(G\times U)\times_U(X\times U) = (G\times X)\times U$ and $(X\times |
97 | U)\times_U (X\times U)$ because pullback preserves products. So, $G\times X\to | 97 | U)\times_U (X\times U) = (X\times X)\times U$ because pullback preserves products. So, $G\times X\to |
98 | X\times X$ is a local isomorphism, hence an isomorphism. | 98 | X\times X$ is a local isomorphism, hence an isomorphism. |
99 | 99 | ||
100 | [^1]: Saunders Mac Lane, Ieke Moerdijk. Sheaves in geometry and logic. Springer, 1994. ISBN: 0-387-97710-4 | 100 | [^1]: Saunders Mac Lane, Ieke Moerdijk. Sheaves in geometry and logic. Springer, 1994. ISBN: 0-387-97710-4 |