# Licensing QIQCOP Zoo uses Apache-2.0 for software and CC BY 4.0 for original catalog content. These licenses apply to different parts of the project; they are not alternative licenses for the same material. ## Software: Apache-2.0 The project's software is distributed under the [Apache License 2.0](LICENSE), subject to the existing notices in [NOTICE](NOTICE). This covers the website generator, API, MCP adapter, web clients, scripts, schemas, tests, deployment configuration, and their technical documentation. Earlier software portions distributed under MIT retain their original permission and copyright notices, reproduced in NOTICE. Distribution of this project under Apache-2.0 does not revoke those permissions or create a new patent grant from the authors of those earlier portions. Dependencies retain their own licenses and notices. ## Original catalog content: CC BY 4.0 New original research text intentionally contributed under this policy is licensed under [Creative Commons Attribution 4.0 International](LICENSE-CONTENT). This includes original problem statements, explanations, progress summaries, and comments in the catalog and its JSON, TeX, website, API, and MCP outputs. Contributors retain their copyright. The license permits redistribution, translation, adaptation, and commercial use with the required attribution, license information, and indication of changes. Follow the license's attribution conditions, including supplied credits, license information, and an indication of changes. Respect a contributor's requested anonymous credit. For academic reuse, we recommend linking to the problem page and preserving its primary-source references. Those citation recommendations do not add license conditions. Credit for the catalog's wording does not imply authorship of the underlying research. The CC license covers only rights the contributor holds or is authorized to license. It does not relicense cited papers, third-party quotations, figures, software, or other separately licensed material. It does not impose new restrictions on mathematical facts or material otherwise free to use. Names and logos are not licensed for use as an endorsement. ## Earlier content and permissions This policy does not retroactively license other contributors' research text. Catalog content contributed before this policy's adoption on main, including the snapshot at `fc49eb0be456043fff8afb629428690e1efa7bde`, is excluded from the new CC BY 4.0 grant unless the relevant rights holders confirm permission. Any existing permissions remain unchanged. Later edits license only the new text whose author has agreed; an edit alone does not license the whole record. Maintainers should record confirmations below with the contributor's public name (or anonymous credit), the exact files/revisions covered, and a public confirmation link or a private permission reference that does not disclose contact details. Git commit authorship by itself is not evidence of permission from every rights holder. Until a record's coverage is confirmed, do not label its entire text or a bulk catalog download as CC BY 4.0. ### PR #38: original 18 problem records On 14 September 2026, bikunli [explicitly confirmed](https://github.com/Naixu-Guo/quantum-open-problems/pull/38#issuecomment-5670932984) that their original text in the 18 new problem records at commit `b4b1d8cc9e48b3a2b9108f5a3e3cc80a99d26eeb` may be published under CC BY 4.0 and that they have the right to contribute it on those terms. The confirmation covers the following records at that revision, including their corresponding TeX mirrors and derived catalog representations: - `database/problems_json/op_0c63e4d2400a95b1.json` - `database/problems_json/op_0ca7986d256cf0df.json` - `database/problems_json/op_1726fa212d725bc8.json` - `database/problems_json/op_1ab8b10386bddd66.json` - `database/problems_json/op_21cb3e1c3ed33976.json` - `database/problems_json/op_2e43f525333b67c0.json` - `database/problems_json/op_38f9dbb6c3f92b0c.json` - `database/problems_json/op_396109643100aaca.json` - `database/problems_json/op_4154bf4cbe0d288e.json` - `database/problems_json/op_58610efec5dbe564.json` - `database/problems_json/op_6690dfacb75e8dc0.json` - `database/problems_json/op_66affd4b198fd445.json` - `database/problems_json/op_722706a9205dcff2.json` - `database/problems_json/op_7eefb7506b175200.json` - `database/problems_json/op_a370855db65d4d24.json` - `database/problems_json/op_a40ad449c54093d7.json` - `database/problems_json/op_d40d1f65b5aaaefd.json` - `database/problems_json/op_eba8dda5ff69d0f2.json` The grant covers only bikunli's original catalog text. Existing and third-party material retain their own terms; this does not extend to other contributors' text or to cited papers. ## Contributions New code contributions use Apache-2.0; new original catalog text uses CC BY 4.0. Contribute only material you are entitled to license this way and clearly identify third-party material and its terms. See [CONTRIBUTING.md](CONTRIBUTING.md). This policy takes effect when adopted on main. Obtain explicit agreement for pending contributions submitted before adoption. The proposal form states the content license before submission. New clients send `contentLicense: "CC-BY-4.0"` with consent; the inbox preserves that value with the receipt. Older proposals without this value remain readable and need permission confirmation before their original wording is published under CC BY. Private contact details are not licensed for publication.