{ localUrl: '../page/even_signed_permutations_form_a_group.html', arbitalUrl: 'https://arbital.com/p/even_signed_permutations_form_a_group', rawJsonUrl: '../raw/4hg.json', likeableId: '0', likeableType: 'page', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], pageId: 'even_signed_permutations_form_a_group', edit: '1', editSummary: '', prevEdit: '0', currentEdit: '1', wasPublished: 'true', type: 'wiki', title: 'The collection of even-signed permutations is a group', clickbait: 'This proves the well-definedness of one particular definition of the alternating group.', textLength: '1041', alias: 'even_signed_permutations_form_a_group', externalUrl: '', sortChildrenBy: 'likes', hasVote: 'false', voteType: '', votesAnonymous: 'false', editCreatorId: 'PatrickStevens', editCreatedAt: '2016-06-17 13:43:40', pageCreatorId: 'PatrickStevens', pageCreatedAt: '2016-06-17 13:43:40', 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: '26', text: 'The collection of elements of the [-497] $S_n$ which are made by multiplying together an even number of permutations forms a subgroup of $S_n$.\n\nThis proves that the [-alternating_group] $A_n$ is well-defined, if it is given as "the subgroup of $S_n$ containing precisely that which is made by multiplying together an even number of transpositions".\n\n# Proof\n\nFirstly we must check that "I can only be made by multiplying together an even number of transpositions" is a well-defined notion; this [4hh is in fact true].\n\nWe must check the group axioms.\n\n- Identity: the identity is simply the product of no transpositions, and $0$ is even.\n- Associativity is inherited from $S_n$.\n- Closure: if we multiply together an even number of transpositions, and then a further even number of transpositions, we obtain an even number of transpositions.\n- Inverses: if $\\sigma$ is made of an even number of transpositions, say $\\tau_1 \\tau_2 \\dots \\tau_m$, then its inverse is $\\tau_m \\tau_{m-1} \\dots \\tau_1$, since a transposition is its own inverse.', 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: [ 'PatrickStevens' ], childIds: [], parentIds: [ 'alternating_group' ], commentIds: [], questionIds: [], tagIds: [], relatedIds: [], markIds: [], explanations: [], learnMore: [], requirements: [ { id: '4117', parentId: 'transposition_in_symmetric_group', childId: 'even_signed_permutations_form_a_group', type: 'requirement', creatorId: 'AlexeiAndreev', createdAt: '2016-06-17 21:58:56', level: '1', isStrong: 'false', everPublished: 'true' }, { id: '4118', parentId: 'symmetric_group', childId: 'even_signed_permutations_form_a_group', type: 'requirement', creatorId: 'AlexeiAndreev', createdAt: '2016-06-17 21:58:56', level: '1', isStrong: 'false', everPublished: 'true' }, { id: '4124', parentId: 'sign_of_permutation_is_well_defined', childId: 'even_signed_permutations_form_a_group', type: 'requirement', creatorId: 'AlexeiAndreev', createdAt: '2016-06-17 21:58:56', level: '1', isStrong: 'false', everPublished: 'true' } ], 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: '13517', pageId: 'even_signed_permutations_form_a_group', userId: 'PatrickStevens', edit: '1', type: 'newParent', createdAt: '2016-06-17 14:14:21', auxPageId: 'alternating_group', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '13501', pageId: 'even_signed_permutations_form_a_group', userId: 'PatrickStevens', edit: '1', type: 'newEdit', createdAt: '2016-06-17 13:43:40', auxPageId: '', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '13497', pageId: 'even_signed_permutations_form_a_group', userId: 'PatrickStevens', edit: '1', type: 'newRequirement', createdAt: '2016-06-17 13:43:39', auxPageId: 'sign_of_permutation_is_well_defined', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '13486', pageId: 'even_signed_permutations_form_a_group', userId: 'PatrickStevens', edit: '1', type: 'newRequirement', createdAt: '2016-06-17 13:16:55', auxPageId: 'symmetric_group', oldSettingsValue: '', newSettingsValue: '' }, { likeableId: '0', likeableType: 'changeLog', myLikeValue: '0', likeCount: '0', dislikeCount: '0', likeScore: '0', individualLikes: [], id: '13485', pageId: 'even_signed_permutations_form_a_group', userId: 'PatrickStevens', edit: '1', type: 'newRequirement', createdAt: '2016-06-17 13:16:47', auxPageId: 'transposition_in_symmetric_group', oldSettingsValue: '', newSettingsValue: '' } ], feedSubmissions: [], searchStrings: {}, hasChildren: 'false', hasParents: 'true', redAliases: {}, improvementTagIds: [], nonMetaTagIds: [], todos: [], slowDownMap: 'null', speedUpMap: 'null', arcPageIds: 'null', contentRequests: {} }