Fine interwiki

(English) This is an essay. It expresses the opinions and ideas of some Wikimedians but may not have wide support. This is not policy on Meta, but it may be a policy or guideline on other Wikimedia projects. Feel free to update this page as needed, or use the discussion page to propose major changes.

For a more up-to-date interwiki system, see Wikidata.

Traditional approach to interlanguage links is to establish an equivalence relation (bidirectional links with transitivity) between articles in different languages such that no different articles in the same language should be equivalent. This implies no duplicate links, and that we may not able to walk to another article of chosen language only via interwiki. Some minor deviations were considered there. Here a new semantic model of interlanguage links is proposed, essentially asymmetric, but based on existing MediaWiki functionality. It may deal with very complicated interlanguage links entanglement.

Philosophy

Main postulates:

• There are some kinds of entities in Wikipedia, such as: articles, their sections, redirects (to articles and to sections), categories and even disambiguation pages.
• Each entity has its thematic scope, which is (generally) language-unspecific.
• Every entity may be, in theory (but not necessary), an object of interwiki: a target (destination) or even a source (this latter needs some technical improvement, at least special templates).
• There are some kinds of links between pairs of entities, with one side called inner (or lower), and the opposite – outer (or upper). These include:
  • Redirection link: a redirect page is inner, its target is outer;
  • Containment: each section (inner) is contained in an article or outer section, an implicit link;
  • Detail link: if a section starts from {{main}} (but not an article itself!), then this section is an outer entity, and linked article is an inner;
  • Category link: a categorized page is an inner entity, and a category itself is an outer entity;
  • Interwiki link: a source is an inner (lower) entity, and the target is an outer (upper) entity.
• Passing from inner side to an outer one should (generally, but not strictly) expand the scope.
• All links between entities form a directed multigraph. It induces a transitive (but not symmetric) binary relation of indirect connection.
• Because of transitivity, there is an equivalence relation of entities, indirectly connected in both directions. In simple cases it exactly corresponds to our old interwiki concept.
• If two entities in the same language is equivalent in the sense of the relation above, then either they must be the same identity or one must redirect to another. So, no essentially distinct entities in one language may be equivalent.
• If we factorize entities by the equivalence above and drop all loops, then the rest will form a directed acyclic graph (more correctly, a multigraph, because some links would duplicate). Ban on directed cycles in this formulation is not a separate requirement, but a consequence of requirements above – if a directed cycle exists, then all its entities are equivalent. So, there is a partial ordering of indirect thematic inclusion.
• Linked articles on different articles may have the same scope and be equivalent, but not necessary. Any language decide itself how to order the content.

Principal cases

Entity type	Target	Source
[[W]] Article	Commonly accepted
# Article    section	Does work, but some bots delete it	Experimental, see w:Template:Section-links
Redirect	Commonly considered as overhead, but may be very useful	Should be avoided
noframe Disambiguation    page	Should be avoided (unless from the same type)	OK, but only to the same type
Category	Last resort (unless from the same type)	OK, but only to the same type
Duplicate links	Should be avoided

Examples

A test case of interlanguage links ordering is currently under development at /Council of Basel-Ferrara-Florence. There are different cases of links and redirects, but no sections is considered yet.