The rational Hodge conjecture for products of K3 surfaces

The proof relies on an adaptation of the flawed stabilization-trace construction in Algebraicity of Weil classes on split abelian eightfolds. The sign error in that construction prevents the required signed-double-point cancellation. The resulting gap leaves this paper’s claimed rational Hodge theorem for products of projective K3 surfaces unproved.

This withdrawal concerns the proof; it does not assert that the mathematical statement is false.