{"id":16314043,"url":"https://github.com/lysxia/cfpt","last_synced_at":"2025-10-31T07:48:49.771Z","repository":{"id":16591112,"uuid":"19345470","full_name":"Lysxia/cfpt","owner":"Lysxia","description":"Counting Functional Pregroup Types","archived":false,"fork":false,"pushed_at":"2014-05-07T12:04:57.000Z","size":136,"stargazers_count":2,"open_issues_count":0,"forks_count":0,"subscribers_count":2,"default_branch":"master","last_synced_at":"2025-04-24T00:57:52.795Z","etag":null,"topics":[],"latest_commit_sha":null,"homepage":null,"language":"Haskell","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":null,"status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/Lysxia.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":null,"code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null}},"created_at":"2014-05-01T13:40:16.000Z","updated_at":"2019-12-08T02:54:29.000Z","dependencies_parsed_at":"2022-09-24T08:21:28.002Z","dependency_job_id":null,"html_url":"https://github.com/Lysxia/cfpt","commit_stats":null,"previous_names":[],"tags_count":0,"template":false,"template_full_name":null,"repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/Lysxia%2Fcfpt","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/Lysxia%2Fcfpt/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/Lysxia%2Fcfpt/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/Lysxia%2Fcfpt/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/Lysxia","download_url":"https://codeload.github.com/Lysxia/cfpt/tar.gz/refs/heads/master","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":250541005,"owners_count":21447427,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2022-07-04T15:15:14.044Z","host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":[],"created_at":"2024-10-10T21:53:04.494Z","updated_at":"2025-10-31T07:48:44.698Z","avatar_url":"https://github.com/Lysxia.png","language":"Haskell","funding_links":[],"categories":[],"sub_categories":[],"readme":"Counting Functional Pregroup Types\n===\n\n_Short version_:\n\nWe consider words on the set `Z` of relative integers.\n\nIn particular, `X` is the smallest set such that\n\n1. It contains the one-letter word `0`.\n\n2. If `a` and `b` are two words of `X`,\nthen `X` also contains `a L(b)` and `R(a) b`.\n\n`L(a)` is obtained by taking the reverse of `a`\nand subtracting one to every letter.\n\n`R(b)` is obtained by taking the reverse of `b`\nand adding one to every letter.\n\n---\n\nFind the number `X(n)` of words of length `n`.\n\n---\n\n*Conjecture*: `X(n) = sum(i = 0 .. n, C(2 * n - i, n + i))`.\n\n`C(n, k)` is the binomial coefficient.\n\nhttp://oeis.org/A108081\n\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Flysxia%2Fcfpt","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Flysxia%2Fcfpt","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Flysxia%2Fcfpt/lists"}