List of proofs of non-trivial theorems which were unnoticed to be wrong for at least a few years

For example, the Weber's proof of Kronecker–Weber theorem. I would like to know such proofs. It seems to be important for me to remember that a widely accepted proof might be wrong.

Solution 1:

There are many variations on this theme in MathOverflow.

Widely accepted mathematical results that were later shown wrong

Failures that lead eventually to new mathematics

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What are some correct results discovered with incorrect or no proofs

Examples where physical heuristics led to incorrect answers

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Retracted mathematics papers

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Mathematicians whose works were criticized by contemporaries but became widely accepted later

What are examples of theorem which were once valid then became invalid as standard definitions shifted

Have we ever lost any mathematics

Examples of conjectures that were widely believed to be true but later proved false

Statements which were given as axioms which later turned out to be false

and for good measure

Smith-Minkowski-Siegel mass formula

Grunwald-Wang theorem

Polygons Flip Finitely: Flaws and a Fix