The purpose of this question is to link to various old (say $\succeq 1$ year old) closed posts, mostly by no longer active users, most of which are reasonable candidates for deletion, and a few for reopening, while it (in most cases) makes little sense to keep them closed and undeleted.

If you have enough reputation, you should be able to cast a deletion or reopening vote ($\ge 10000$ for deletion [needs 3 votes], $\ge 3000$ for reopening [needs 5 votes]). The deleting option is present under some conditions: for closed questions I think it's automatic if the score is $\le -3$, and in other cases depends on parameters (OP's rep? age of the question?) in some way I don't know (edit: some info here); also at $\ge 125$ reputation you can downvote, which in some cases can eventually lead to automatic deletion.

(I'd avoid here very active questions for which closure may have been disputed.)

I'll use answers to make such partial lists (usually of posts in a given subject, e.g., detected by some given tag). (Of course one can post "real" answers!) At some point I'll make updates indicating deleted/reopened questions, if applicable.


Here are the closed questions tagged (at this date) with the deprecated .

finite index, self-normalizing subgroup of $F_2$

Why do we not lose any generality by proving it only for finitely generated groups

(not closed but downvoted) Group associated to the monoid $({\cal P}(X\times X), \circ)$

Making idempotent element by a relation

How to solve this system of equations?

How to show the set $\operatorname{Hom}_K(L,\bar{K})$ of all $K$-embeddings of $L$ is partitioned into $m$ equivalence classes of $d$ elements each?

Is the "algebraic closure" of the quaternions, finite dimensional?

Is there any construction of infinite dimensional algebraic division ring?

Polynomial constraints triggered by irreducibility

Does this solution guarantee $det(A)=0$ where $A\in M(R)$?

Is $K\cap \langle H\cup N\rangle‎\subseteq‎ \langle H\cup (K\cap N)\rangle$?

Properties of colon ideal

Diagonalize the simultaneous matrices and its background

Learning Algebra & Group Theory on my own

now deleted https://mathoverflow.net/questions/47534/unit-ideal-in-non-commutative-rings

now deleted https://mathoverflow.net/questions/157122/algebra-generated-by-a-tree-edit

now deleted https://mathoverflow.net/questions/127611/an-exercise-about-tor

now deleted https://mathoverflow.net/questions/266080/does-alexander-whitney-formula-imply-pythagoras-theorem

  • 1
    $\begingroup$ mathoverflow.net/questions/88660/ring-of-a-spectral-space is currently open: was it closed when you wrote your original list? $\endgroup$ – Yemon Choi Feb 9 at 20:02
  • $\begingroup$ @YemonChoi no, it was never closed. -- You can see this in the timeline, which is now linked to below the vote score. $\endgroup$ – Stefan Kohl Feb 9 at 20:11
  • 2
    $\begingroup$ @YemonChoi thank you! it seems to be a copying error (it's neither downvoted nor closed, nor any particular reason to include it here) – this list was manually picked among the list of 260 question tagged 'abstract-algebra'. The given item is now deleted from the above list – despite being copied here since yesterday it duly got no closing vote. $\endgroup$ – YCor Feb 9 at 20:25

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .