Abstract
F. Campana had asked whether a certain threefold is rational. F. Catanese, K. Oguiso and T. T. Truong have recently shown that this variety is birational to a specific conic bundle threefold, which they show is unirational. Computing residues of elements in the Brauer group of the function field of the plane, I prove that that conic bundle threefold is birational to another conic bundle threefold, and the latter is clearly a rational variety.
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References
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