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| author | Preston Pan <ret2pop@nullring.xyz> | 2026-04-11 13:14:04 -0700 |
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| committer | Preston Pan <ret2pop@nullring.xyz> | 2026-04-11 13:14:04 -0700 |
| commit | 55e29f03ac3b537843f85892a1323e1f46321675 (patch) | |
| tree | e5796f03eaacb351fa8d8c612f852717ada4d2d6 /mindmap/Proper Mapping.org | |
| parent | f17203b32bd1ecb0d908bbf03b9239e2efde59d6 (diff) | |
new articles and snippets
Diffstat (limited to 'mindmap/Proper Mapping.org')
| -rw-r--r-- | mindmap/Proper Mapping.org | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/mindmap/Proper Mapping.org b/mindmap/Proper Mapping.org new file mode 100644 index 0000000..633ce5e --- /dev/null +++ b/mindmap/Proper Mapping.org @@ -0,0 +1,14 @@ +:PROPERTIES: +:ID: 86bab66a-6f30-4330-966f-3ac319344602 +:ROAM_ALIASES: "proper map" +:END: +#+title: Proper Mapping +#+author: Preston Pan +#+description: It's proper and it's a map. +#+options: broken-links:t +* Introduction +Here is the definition: +#+begin_definition +If $f$ is a [[id:fdcecb13-35e1-439c-ba13-5c63bd7342c3][mapping]] on a [[id:b0784577-9691-4c8e-a8e4-974a7c9c4949][topological space]] $X$, then $f$ is proper if for all [[id:72deb4cd-46f7-4ef2-9c66-6943e47a9e83][compact]] sets $K \subset X$, $f^{-1}(K)$ is compact. +#+end_definition +We care about this definition because for some reason it is useful sometimes. |