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Martin Sleziak
Martin Sleziak
5:00 AM
A new tag reference was created. Since reference-request already exists, there is no need for the new tag, so I'll remove it.
0
Q: Blow up of ideal sheaves

SD..Is there a birational projective morphism between reduced (not necessarily irreducible) quasi-projective varities which is not a blow up along some ideal sheaf?

ag.algebraic-geometry reference-request ac.commutative-algebra reference
Another newly created tag is semiabelian-categories - this tag seems reasonable.
 
Martin Sleziak
Martin Sleziak
5:52 AM
I see that François G. Dorais continues with removal of geometry tag mentioned here:
2 days ago, by François G. Dorais
The 30+ questions in the search below can probably be fixed my removing geometry and adding geometric-probability: https://mathoverflow.net/questions/tagged/geometry+pr.probability+-geometric-pro‌​bability
Like mathoverflow.net/posts/130446/revisions or mathoverflow.net/posts/130763/revisions. So we may expect that geometry tag gets closer to 400 thanks to this activity.
specific-question I have removed discrete-mathematics (deprecated) here, and added discrete-geometry and covering: How to cover a set in a grid with as few rectangles as possible? Still I'll be grateful if there are some suggestions how to improve tagging of that question.
2
Q: How to cover a set in a grid with as few rectangles as possible?

Penghui YaoIn calculus, when estimating a area of a set in a 2-dimensional space, we use rectangles to approximate. To get sufficient precision, how many rectangles are needed if the shape of the set is close to a rectangle? I formalize the discrete version of the problem as follows. Suppose we have a $...

co.combinatorics discrete-geometry covering
BTW the word covering has several various meanings in mathematics and the tag-info is empty so it is not clear what exactly is the intended usage. This question seems to me close to packing a covering, which is a topic in discrete geometry (and probably there are also some other related areas).
 
 
7 hours later…
Todd Trimble
Todd Trimble
1:02 PM
@MartinSleziak People seem to be using the tag however they like, which makes it virtually impossible to provide tag info as things stand. But the main division seems to be between covering maps/spaces in algebraic topology and uses in discrete math, so the solution may involve first re-tagging some of those as covering-spaces.
 
Martin Sleziak
Martin Sleziak
I do not know much about those topics, but my impression was that packings and coverings are to some extent related. So maybe it would make sense to have a single tag packing-and-covering...? (But probably it would be better to hear opinion from some experts on this.)
On math.SE we have a tag named packing-problem. I don't see a tag for coverings in the sense they are used in discrete geometry.
 

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