Retracted Mathematics Papers Can anyone cite an example of a mathematics paper that has been retracted?
It is said that on the order of 100,000 new theorems enter the mathematics literature every year. For a number of reasons including hyper-specialization and demands on referee resources it is, in my view, unlikely that all their proofs are correct.  Yet it seems no explicit effort is made to clean the literature.  False theorms float downstream along with the true ones, available for citation and use in constructing yet further theorems.
Thanks for any insight.
Cheers, Scott
 A: A general existence theorem is proved :
1933 : W. Grunwald, Ein allgemeines Existenztheorem für algebraische Zahlkörper, J. reine angew. Math. 169 (1933), 103–107.
and reproved :
1942: G. Whaples, Non-analytic class field theory and Grünwald's theorem. 
Duke Math. J. 9, (1942). 455–473. 
A counter-example is found :
1948 : S. Wang, A counter-example to Grunwald's theorem, Ann. Math. 49 (1948), 1008–1009. 
and the theorem is corrected :
1950 : S. Wang, On Grunwald's theorem, Ann. Math. 51 (1950), 471–484.
twice in the same year :
---- : H. Hasse, Zum Existenzsatz von Grunwald in der Klassenkörpertheorie, J. reine angew. Math. 188 (1950), 40–64.
A quarter of a century later, a simpler proof is given :
1974: J. Neukirch, Eine Bemerkung zum Existenzsatz von Grunwald-Hasse-Wang, J. Reine Angew. Math. 268/269 (1974), 315–317. 
but more than half a century later, corrections to the corrections are required :
2007 : W-D. Geyer & C. Jensen, Embeddability of quadratic extensions in cyclic extensions.
Forum Math. 19 (2007), no. 4, 707–725. 
2011 : P. Morton, A correction to Hasse's version of the Grunwald-Hasse-Wang theorem. 
J. Reine Angew. Math. 659 (2011), 169–174. 
Addendum (2013/05/18)
I'm afraid the above list of errors and corrections might look a bit negative, so let me add a positive note (which will also save you 30,00 € or $42.00 by not having to read it here) :
In 1933, van der Waerden asked in the Jahresbericht : Which quadratic fields can be embedded in cyclic quartic fields ?  Solutions were provided by four people, among them Hasse, who generalised the problem to : Under which conditions can a degree-$l$ ($l$ prime) cyclic extension $K_1$ of a number field $K$ be embedded into a degree-$l^n$ cyclic extension $K_n$ of $K$ ?
A. Scholz sent in a "solution" to this problem in 1935 which essentially claimed that the obstructions are purely local in nature.  But Hans Richter, a doctoral student of van der Waerden, knew already that there is an exception when $l=2$, so a Scholtz-Richter correction to Scholz's paper was required.  In a sense, Richter anticipated not only Wang's counterexample to Grunwald's theorem but also its solution, without mentioning it explicitly as such.
A: You have to notice that many of those theorems are dead-ends. They'll either not be used at all, or be superseded by a better one. Corrections sometimes happen, but it looks like pure changes of focus is also a big factor.
How many proofs have there been that given a point and a line, there is a single line parallel to the line going through the point, before non-euclidean geometry settled the matter?
Consider the vast litterature on proving that such and such type of polynomial can be solved by radicals. Galois theory made (almost) all of these obsolete -- be they right or wrong.
The notions of limits, continuity, derivability, etc... had no serious definition for very long, before people started to realize there were problems (like sequence of continuous functions converging to a non-continuous limit) and the $(\varepsilon,\delta)$ definitions were given, and people started to prove more solid results through this framework.
The italian school of algebraic geometry is another example coming to mind, where things were cleaned by a quite radical change in the paradigms of the field.
In fact, one could say that most of mathematics is about trying to get correct theorems out, and clean what is already there through obsolescence, be it gentle(correction) or cataclysmic(not interesting anymore).
As a final remark, I think it is reasonable to expect the recent works in automatic proof-checkers/proof-builders will sparkle a new revolutionary era.
A: Here are some recent (not famous) examples of papers that have been retracted at the request of the Editor-in-Chief or the Publisher:
http://www.sciencedirect.com/science/article/pii/S089396591000265X
http://www.sciencedirect.com/science/article/pii/S0393044011002233
http://www.sciencedirect.com/science/article/pii/S0022247X12001254
http://www.sciencedirect.com/science/article/pii/S0166218X1100309X
http://www.sciencedirect.com/science/article/pii/S0898122112003008
I found them via the blog Retraction Watch, which also contains ample discussion about reasons and policies about retracting papers and many more examples, including background information.
