As of August 8, 2017, the length limit for tags went from 25 characters to 35 characters. So now is a great time to allow inconveniently compressed tag names to stretch out a bit...
Perhaps we could collect here list of tags which now, after the character limit for length of tag name has been extended, could be spelled in full instead of a shortening. (This answer is CW - feel free to edit in here various tags that are currently shortened.)
Among possible suspects are the tags with name of length 25 - they can be found by this SEDE query: Tags with given length of name. (However, not all shortened tags use exactly 25 characters. Two examples are computational-group-theo or infinite-dim-manifolds.)
Shortenings to be expanded
- gch vs. generalized-continuum-hypothesis (Both names should be kept here with a synonym in one or the other direction. After all, people around here know what GCH is, so it probably can remain the master tag. But adding a synonym might be useful addition, since people looking for the tag corresponding to their might start to write something liked "continuum hypothesis" in the tag field.)
- dg-algebras $\to$ differential-graded-algebras, dg-categories $\to$ differential-graded-categories (Maybe shortened names could be kept as synonyms - since MO users are probably used to them by now?)
- stochastic-diff-equations $\to$ stochastic-differential-equations
Shortening which moderators already replaced
- cartesian-closed $\to$ cartesian-closed-categories
- classical-invariant-theor $\to$ classical-invariant-theory
- combinatorial-group-theor $\to$ combinatorial-group-theory
- combinatorial-hopf-algebr $\to$ combinatorial-hopf-algebras
- combinatorial-number-theo $\to$ combinatorial-number-theory
- combinatorial-optimizatio $\to$ combinatorial-optimization
- computational-group-theo $\to$ computational-group-theory
- computational-number-theo $\to$ computational-number-theory
- derived-algebraic-geometr $\to$ derived-algebraic-geometry
- differential-galois-theor $\to$ differential-galois-theory
- differential-graded-lie-a $\to$ differential-graded-lie-algebras
- infinite-dim-manifolds $\to$ infinite-dimensional-manifolds
- infinite-time-computabili $\to$ infinite-time-computability
- modular-rep-theory $\to$ modular-representation-theory
- multiplicative-number-the $\to$ multiplicative-number-theory
- probabilistic-number-theo $\to$ probabilistic-number-theory
- pseudo-differential-opera $\to$ pseudo-differential-operators
- symmetric-monoidal-catego $\to$ symmetric-monoidal-categories
- transcend.-number-theory $\to$ transcendental-number-theory1
Synonyms with names longer than 25 characters
1There is a separate discussion whether there could be a better name for this tag: The tags (transcendence) and (transcendental-number-theory).