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" } ], "id": "https://mathstodon.xyz/users/varkor/statuses/110474588808548742", "type": "Note", "summary": null, "inReplyTo": "https://mathstodon.xyz/users/jonmsterling/statuses/110467908157993889", "published": "2023-06-02T12:20:47Z", "url": "https://mathstodon.xyz/@varkor/110474588808548742", "attributedTo": "https://mathstodon.xyz/users/varkor", "to": [ "https://www.w3.org/ns/activitystreams#Public" ], "cc": [ "https://mathstodon.xyz/users/varkor/followers", "https://mathstodon.xyz/users/ltchen", "https://mathstodon.xyz/users/jonmsterling" ], "sensitive": false, "atomUri": "https://mathstodon.xyz/users/varkor/statuses/110474588808548742", "inReplyToAtomUri": "https://mathstodon.xyz/users/jonmsterling/statuses/110467908157993889", "conversation": "tag:mathstodon.xyz,2023-06-01:objectId=52387619:objectType=Conversation", "content": "<p><span class=\"h-card\" translate=\"no\"><a href=\"https://mathstodon.xyz/@jonmsterling\" class=\"u-url mention\">@<span>jonmsterling</span></a></span> <span class=\"h-card\" translate=\"no\"><a href=\"https://mathstodon.xyz/@ltchen\" class=\"u-url mention\">@<span>ltchen</span></a></span> My impression is that the more set-theoretic aspects of locally presentable categories arise, at least primarily, when one does not fix the cardinality of presentability. In contrast, much of the theory of locally \\(\\lambda\\)-presentable categories, for a fixed \\(\\lambda\\), can be derived 2-category theoretically without set-theoretic assumptions. In my experience, many of the applications of locally presentable categories do not require a change of cardinal (particularly in computer science). So perhaps the obstructions to constructivity are not as severe as might be feared at first. (On the other hand, the theory of accessible categories seems much more reliant on freely changing cardinality.)</p>", "contentMap": { "en": "<p><span class=\"h-card\" translate=\"no\"><a href=\"https://mathstodon.xyz/@jonmsterling\" class=\"u-url mention\">@<span>jonmsterling</span></a></span> <span class=\"h-card\" translate=\"no\"><a href=\"https://mathstodon.xyz/@ltchen\" class=\"u-url mention\">@<span>ltchen</span></a></span> My impression is that the more set-theoretic aspects of locally presentable categories arise, at least primarily, when one does not fix the cardinality of presentability. In contrast, much of the theory of locally \\(\\lambda\\)-presentable categories, for a fixed \\(\\lambda\\), can be derived 2-category theoretically without set-theoretic assumptions. In my experience, many of the applications of locally presentable categories do not require a change of cardinal (particularly in computer science). So perhaps the obstructions to constructivity are not as severe as might be feared at first. (On the other hand, the theory of accessible categories seems much more reliant on freely changing cardinality.)</p>" }, "updated": "2023-06-02T16:06:01Z", "attachment": [], "tag": [ { "type": "Mention", "href": "https://mathstodon.xyz/users/jonmsterling", "name": "@jonmsterling" }, { "type": "Mention", "href": "https://mathstodon.xyz/users/ltchen", "name": "@ltchen" } ], "replies": { "id": "https://mathstodon.xyz/users/varkor/statuses/110474588808548742/replies", "type": "Collection", "first": { "type": "CollectionPage", "next": "https://mathstodon.xyz/users/varkor/statuses/110474588808548742/replies?only_other_accounts=true&page=true", "partOf": "https://mathstodon.xyz/users/varkor/statuses/110474588808548742/replies", "items": [] } }, "likes": { "id": "https://mathstodon.xyz/users/varkor/statuses/110474588808548742/likes", "type": "Collection", "totalItems": 4 }, "shares": { "id": "https://mathstodon.xyz/users/varkor/statuses/110474588808548742/shares", "type": "Collection", "totalItems": 2 } }