{ localUrl: '../page/function_image.html', arbitalUrl: 'https://arbital.com/p/function_image', rawJsonUrl: '../raw/3lh.json', likeableId: '2491', likeableType: 'page', myLikeValue: '0', likeCount: '1', dislikeCount: '0', likeScore: '1', individualLikes: [ 'EricRogstad' ], pageId: 'function_image', edit: '7', editSummary: '', prevEdit: '6', currentEdit: '7', wasPublished: 'true', type: 'wiki', title: 'Image (of a function)', clickbait: '', textLength: '1180', alias: 'function_image', externalUrl: '', sortChildrenBy: 'likes', hasVote: 'false', voteType: '', votesAnonymous: 'false', editCreatorId: 'NateSoares', editCreatedAt: '2016-06-10 16:45:50', pageCreatorId: 'NateSoares', pageCreatedAt: '2016-05-13 23:17:23', seeDomainId: '0', editDomainId: 'AlexeiAndreev', submitToDomainId: '0', isAutosave: 'false', isSnapshot: 'false', isLiveEdit: 'true', isMinorEdit: 'false', indirectTeacher: 'false', todoCount: '0', isEditorComment: 'false', isApprovedComment: 'true', isResolved: 'false', snapshotText: '', anchorContext: '', anchorText: '', anchorOffset: '0', mergedInto: '', isDeleted: 'false', viewCount: '51', text: 'The image $\\operatorname{im}(f)$ of a [3jy function] $f : X \\to Y$ is the set of all possible outputs of $f$, which is a subset of $Y$. Using [3lj set builder notation], $\\operatorname{im}(f) = \\{f(x) \\mid x \\in X\\}.$\n\nVisualizing a function as a map that takes every point in an input set to one point in an output set, the image is the set of all places where $f$-arrows land (pictured as the yellow subset of $Y$ in the image below).\n\n![Domain, Codomain, and Image](http://i.imgur.com/ZZgVHaI.png)\n\nThe image of a function is not to be confused with the [3lg codomain], which is the _type_ of output that the function produces. For example, consider the [43x Ackermann function], which is a very fast-growing (and difficult to compute) function. When someone asks what sort of thing the Ackermann function produces, the natural answer is not "something from a sparse and hard-to-calculate set of numbers that I can't tell you off the top of my head"; the natural answer is "it outputs a number." In this case, the codomain is "number", while the image is the sparse and hard-to-calculate subset of numbers. For more on this distinction, see the page on [3lv codomain vs image].', metaText: '', isTextLoaded: 'true', isSubscribedToDiscussion: 'false', isSubscribedToUser: 'false', isSubscribedAsMaintainer: 'false', discussionSubscriberCount: '1', maintainerCount: '1', userSubscriberCount: '0', lastVisit: '', hasDraft: 'false', votes: [], voteSummary: 'null', muVoteSummary: '0', voteScaling: '0', currentUserVote: '-2', voteCount: '0', lockedVoteType: '', maxEditEver: '0', redLinkCount: '0', lockedBy: '', lockedUntil: '', nextPageId: '', prevPageId: '', usedAsMastery: 'false', proposalEditNum: '0', permissions: { edit: { has: 'false', reason: 'You don't have domain permission to edit this page' }, proposeEdit: { has: 'true', reason: '' }, delete: { has: 'false', reason: 'You don't have domain permission to delete this page' }, comment: { has: 'false', reason: 'You can't comment in this domain because you are not a member' }, proposeComment: { has: 'true', reason: '' } }, summaries: {}, creatorIds: [ 'NateSoares' ], childIds: [ 'codomain_vs_image' ], parentIds: [ 'function' ], commentIds: [ '3lp' ], questionIds: [], tagIds: [ 'needs_clickbait_meta_tag', 'definition_meta_tag' ], relatedIds: [], markIds: [], explanations: [], learnMore: [], requirements: [], subjects: [], lenses: [], lensParentId: '', pathPages: [], learnMoreTaughtMap: {}, learnMoreCoveredMap: {}, learnMoreRequiredMap: {}, editHistory: {}, domainSubmissions: {}, answers: [], answerCount: '0', commentCount: '0', newCommentCount: '0', linkedMarkCount: '0', changeLogs: [ { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '17151', pageId: 'function_image', userId: 'EricBruylant', edit: '0', type: 'newTag', createdAt: '2016-07-19 02:20:46', auxPageId: 'needs_clickbait_meta_tag', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '12339', pageId: 'function_image', userId: 'NateSoares', edit: '7', type: 'newEdit', createdAt: '2016-06-10 16:45:50', auxPageId: '', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '10310', pageId: 'function_image', userId: 'NateSoares', edit: '6', type: 'newEdit', createdAt: '2016-05-14 05:12:34', auxPageId: '', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '10308', pageId: 'function_image', userId: 'NateSoares', edit: '5', type: 'newEdit', createdAt: '2016-05-14 04:33:41', auxPageId: '', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '10307', pageId: 'function_image', userId: 'NateSoares', edit: '4', type: 'newEdit', createdAt: '2016-05-14 01:43:47', auxPageId: '', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '10299', pageId: 'function_image', userId: 'NateSoares', edit: '3', type: 'newChild', createdAt: '2016-05-14 01:37:54', auxPageId: 'codomain_vs_image', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '10295', pageId: 'function_image', userId: 'NateSoares', edit: '3', type: 'newEdit', createdAt: '2016-05-14 01:02:59', auxPageId: '', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '10249', pageId: 'function_image', userId: 'NateSoares', edit: '2', type: 'newEdit', createdAt: '2016-05-13 23:26:18', auxPageId: '', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '10243', pageId: 'function_image', userId: 'NateSoares', edit: '1', type: 'newEdit', createdAt: '2016-05-13 23:17:23', auxPageId: '', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '10240', pageId: 'function_image', userId: 'NateSoares', edit: '1', type: 'newParent', createdAt: '2016-05-13 23:17:06', auxPageId: 'function', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '10239', pageId: 'function_image', userId: 'NateSoares', edit: '1', type: 'newTag', createdAt: '2016-05-13 23:17:04', auxPageId: 'definition_meta_tag', oldSettingsValue: '', newSettingsValue: '' } ], feedSubmissions: [], searchStrings: {}, hasChildren: 'true', hasParents: 'true', redAliases: {}, improvementTagIds: [], nonMetaTagIds: [], todos: [], slowDownMap: 'null', speedUpMap: 'null', arcPageIds: 'null', contentRequests: { fewerWords: { likeableId: '3687', likeableType: 'contentRequest', myLikeValue: '0', likeCount: '1', dislikeCount: '0', likeScore: '1', individualLikes: [], id: '140', pageId: 'function_image', requestType: 'fewerWords', createdAt: '2016-11-04 11:22:08' }, moreTechnical: { likeableId: '3688', likeableType: 'contentRequest', myLikeValue: '0', likeCount: '1', dislikeCount: '0', likeScore: '1', individualLikes: [], id: '141', pageId: 'function_image', requestType: 'moreTechnical', createdAt: '2016-11-04 11:22:27' } } }