# Multiple categories

Guideline A page can be in multiple categories, but in only one category within a single line of the category hierarchy.
Add'l info A line is what your finger would touch if you were to trace it following the hierarchy from any category up to the root/contents category.

The root or contents category is the largest category in which every line of the category hierarchy ends.

Examples For Example:
Category:A → Category:B → Category:C → Category:D
Category:E
Category:F → Category:G
Category:H


In the above model, a page in categories D, E, and F cannot go into categories A, B, C, G, or H.

Alternately, the page could go into categories G and H, but then not in category F.

Category:A → Category:B → Category:C → Category:D
Category:E
Category:F → Category:G
Category:H


## Approvals

• I agree that reducing category hierarchy redundancy should be used for this guideline. -- Peter Rawsthorne 15:17, 24 July 2009 (UTC)

## Discussion

This is to prevent redundancy, which has the tendency of making the categorisation more confusing. --Jesse Groppi 02:20, 15 July 2009 (UTC)

Can anyone suggest a better way to word this guideline? --Jesse Groppi 02:20, 15 July 2009 (UTC)

My preference would be rewording to avoid negative framework. Here's a suggestion: "A page can be in multiple categories, but in only one category within a single branch of the category hierarchy." --Alison Snieckus 00:56, 25 July 2009 (UTC)
What do you mean by "negative framework"? --Jesse Groppi 19:11, 29 July 2009 (UTC)
It seemed that describing the limitations of what would satisfy the guideline might be simpler and more concise than describing what would not satisfy it. Negative framework overstates it and is probably besides the point. I'm suggesting changing the sentence structure from "...but, not..." to "...but, in only...". --Alison Snieckus 22:17, 29 July 2009 (UTC)
I think I see what you're saying, but I'm not sure "branch" is the right term to use in that way. It has multiple definitions in this sense, and the guideline doesn't apply to all of them. What about this: "A page can be in multiple categories, but in only one category within a single line of the category hierarchy." We can define the term "line" with "A line is what your finger would touch if you were to trace it following the hierarchy from any category up to the root/contents category."
--Jesse Groppi 23:29, 29 July 2009 (UTC)
I like the word 'line' and its very physical definition, "...what your finger would touch...". The new wording seems more concise and understandable. Thanks. --Alison Snieckus 00:35, 30 July 2009 (UTC)