ActivityPub Viewer

A small tool to view real-world ActivityPub objects as JSON! Enter a URL or username from Mastodon or a similar service below, and we'll send a request with the right Accept header to the server to view the underlying object.

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{ "@context": [ "https://www.w3.org/ns/activitystreams", { "ostatus": "http://ostatus.org#", "atomUri": "ostatus:atomUri", "inReplyToAtomUri": "ostatus:inReplyToAtomUri", "conversation": "ostatus:conversation", "sensitive": "as:sensitive", "toot": "http://joinmastodon.org/ns#", "votersCount": "toot:votersCount", "Hashtag": "as:Hashtag" } ], "id": "https://mathstodon.xyz/users/joshuagrochow/statuses/113307081389225241", "type": "Note", "summary": null, "inReplyTo": null, "published": "2024-10-14T18:00:54Z", "url": "https://mathstodon.xyz/@joshuagrochow/113307081389225241", "attributedTo": "https://mathstodon.xyz/users/joshuagrochow", "to": [ "https://www.w3.org/ns/activitystreams#Public" ], "cc": [ "https://mathstodon.xyz/users/joshuagrochow/followers" ], "sensitive": false, "atomUri": "https://mathstodon.xyz/users/joshuagrochow/statuses/113307081389225241", "inReplyToAtomUri": null, "conversation": "tag:mathstodon.xyz,2024-10-14:objectId=118830937:objectType=Conversation", "content": "<p>The notion of epimorphism can be quite different from surjection, e.g. in Rings. </p><p>Though I recently learned epimorphisms can be characterized in terms of Isbell&#39;s zig-zags: <a href=\"https://en.wikipedia.org/wiki/Isbell%27s_zigzag_theorem\" target=\"_blank\" rel=\"nofollow noopener noreferrer\" translate=\"no\"><span class=\"invisible\">https://</span><span class=\"ellipsis\">en.wikipedia.org/wiki/Isbell%2</span><span class=\"invisible\">7s_zigzag_theorem</span></a>.</p><p>Whereas monic seems to capture the notion of &quot;injective&quot; quite well in a categorical def. And indeed the two agree on any variety of algebras in the sense of universal algebra.</p><p><a href=\"https://mathstodon.xyz/tags/algebra\" class=\"mention hashtag\" rel=\"tag\">#<span>algebra</span></a> <a href=\"https://mathstodon.xyz/tags/CategoryTheory\" class=\"mention hashtag\" rel=\"tag\">#<span>CategoryTheory</span></a> <a href=\"https://mathstodon.xyz/tags/UniversalAlgebra\" class=\"mention hashtag\" rel=\"tag\">#<span>UniversalAlgebra</span></a> <a href=\"https://mathstodon.xyz/tags/math\" class=\"mention hashtag\" rel=\"tag\">#<span>math</span></a></p>", "contentMap": { "en": "<p>The notion of epimorphism can be quite different from surjection, e.g. in Rings. </p><p>Though I recently learned epimorphisms can be characterized in terms of Isbell&#39;s zig-zags: <a href=\"https://en.wikipedia.org/wiki/Isbell%27s_zigzag_theorem\" target=\"_blank\" rel=\"nofollow noopener noreferrer\" translate=\"no\"><span class=\"invisible\">https://</span><span class=\"ellipsis\">en.wikipedia.org/wiki/Isbell%2</span><span class=\"invisible\">7s_zigzag_theorem</span></a>.</p><p>Whereas monic seems to capture the notion of &quot;injective&quot; quite well in a categorical def. And indeed the two agree on any variety of algebras in the sense of universal algebra.</p><p><a href=\"https://mathstodon.xyz/tags/algebra\" class=\"mention hashtag\" rel=\"tag\">#<span>algebra</span></a> <a href=\"https://mathstodon.xyz/tags/CategoryTheory\" class=\"mention hashtag\" rel=\"tag\">#<span>CategoryTheory</span></a> <a href=\"https://mathstodon.xyz/tags/UniversalAlgebra\" class=\"mention hashtag\" rel=\"tag\">#<span>UniversalAlgebra</span></a> <a href=\"https://mathstodon.xyz/tags/math\" class=\"mention hashtag\" rel=\"tag\">#<span>math</span></a></p>" }, "attachment": [], "tag": [ { "type": "Hashtag", "href": "https://mathstodon.xyz/tags/math", "name": "#math" }, { "type": "Hashtag", "href": "https://mathstodon.xyz/tags/universalalgebra", "name": "#universalalgebra" }, { "type": "Hashtag", "href": "https://mathstodon.xyz/tags/categorytheory", "name": "#categorytheory" }, { "type": "Hashtag", "href": "https://mathstodon.xyz/tags/algebra", "name": "#algebra" } ], "replies": { "id": "https://mathstodon.xyz/users/joshuagrochow/statuses/113307081389225241/replies", "type": "Collection", "first": { "type": "CollectionPage", "next": "https://mathstodon.xyz/users/joshuagrochow/statuses/113307081389225241/replies?min_id=113307082296952699&page=true", "partOf": "https://mathstodon.xyz/users/joshuagrochow/statuses/113307081389225241/replies", "items": [ "https://mathstodon.xyz/users/joshuagrochow/statuses/113307082296952699" ] } }, "likes": { "id": "https://mathstodon.xyz/users/joshuagrochow/statuses/113307081389225241/likes", "type": "Collection", "totalItems": 4 }, "shares": { "id": "https://mathstodon.xyz/users/joshuagrochow/statuses/113307081389225241/shares", "type": "Collection", "totalItems": 2 } }