Docs / Problems built on other problems
Problems built on other problems
A new problem may declare up to 5 parent problems it builds on, in any field. The declaration is part of the record you sign: each parent is pinned at the revision you saw, with a relation and a one-line note on what differs. It never changes afterwards, and the parent's page lists your problem once an editor accepts it. There is no separate "fork" object and nothing asks the parent's author for permission: a public problem may be built on by anyone.
The four relations
| Relation | Your page says | The parent lists yours under | When |
|---|---|---|---|
special_case | Special case of P | Special cases | Yours fixes a parameter, a regime or a model the parent leaves open. |
generalization | Generalizes P | Generalizations | Yours drops or widens an assumption of the parent, so the parent is one case of it. |
combination | Combines P | Combined into | Yours joins two or more parents into one question; it needs at least two parents marked so. |
variant | Variant of P | Variants | Yours changes the question in another way: another observable, another system, another settling result. |
Declaring parents
- From a problem page: "Make a variant" opens a new problem with that problem as its parent (relation variant, which you may change) and its topic preset. The form opens empty: you write your own text, with the parent's text beside it for reference, and you may quote it. There is no file and no AI proposal; you may let AI screen what you sign.
- When submitting: the form of a new problem has an optional "Parent problems" block. Search the published problems, or use "Check for similar problems" and add one of its suggestions.
The declaration is checked when you prepare the record, when you open the ORCID sign-in and again when it completes:
- at most 5 parents, each a different problem;
- each parent is public, not removed, and its displayed revision was not rejected; the revision you pin is a public revision of it (normally the displayed one);
- each note is one line of 1 to 300 characters;
- "Combines" is on at least two parents or on none;
- yours asks a different question from each parent, whatever the relation: the precise statement, what would settle it, the kind or the expected answer must differ. A reworded copy is refused.
The record names each pinned parent revision among its parents (with your upload, if you uploaded a file), so anyone can check the declaration against the log (the protocol).
How it is checked
A problem with parents goes through the same screening and review as any new problem. With your consent the screening also sees each relation and note, and a parent's title and the start of its precise statement when that text may be sent (a seed problem, or one whose author allowed it); when it is unsure whether a relation is right, an editor decides before anything is published. Only the consent texts that name parent problems (the current text asked with an upload, and the one for a variant) cover this; under an earlier consent nothing about the parents is sent and an editor screens the problem. An editor's acceptance covers the declaration: a well-posed problem, correctly related to each parent. A wrong relation is a rejection with a reason, which you may appeal, and you may submit again; an editor cannot detach a parent. The editor sees, for each parent, the relation, your note, the pinned revision and a word-by-word comparison of the precise statements and of what would settle them. The parent's author is not excluded from deciding; the interest is shown.
What the pages show
- Your problem's page lists its parents with the relation, the parent's status, your note and the revision you pinned. When the parent's displayed revision states another question than the one you pinned, it says "parent revised since"; a change of wording only does not count.
- It also shows the results posted on each parent, read-only, up to 10 per parent with a link to the rest. A result on your problem may cite them.
- The parent's page lists the problems built on it under "Problems built on this one", grouped by relation, with their status and "unreviewed" until an editor accepts them. Rejected and removed problems are not listed.
- When a parent is removed by moderation your problem stays; its page says that a parent problem was removed, and the parent's results leave it.
No status passes between them
A parent and its children are separate questions, and each has its own status from its own results. A solution of a special case does not solve the general problem, and a disproof of a generalization does not disprove its special cases unless an editor accepts a result saying so on that problem. For example, if a problem asks for the critical temperature in a model and a special case fixes one coupling, a verified solution of the special case leaves the general problem open; a result on the general problem may cite it.
Notifications
- When an editor accepts a problem built on yours, you and the followers of your problem are told, once per parent ("3 new problems build on P"); nothing is sent when it is only published.
- When a parent of your problem is removed, you are told; its followers are not.