Quég​uiner-Mathieu–Semenov–Zainoulline conjecture on the J-invariant after generic splitting

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Let (A,σ)(A,\sigma) be a central simple algebra with orthogonal involution and trivial discriminant, and let G=PGO⁡+(A,σ)G=\operatorname{PGO}^+(A,\sigma) be the connected component of its automorphism group, an adjoint group of type DnD_n. Write

J(G)=(j1,…,jr).J(G)=(j_1,\ldots,j_r).

Let FAF_A be the function field of the Severi–Brauer variety of AA, a generic splitting field of AA, and denote by (ji)FA(j_i)_{F_A} the ii-th component of the JJ-invariant after extension to FAF_A. Quég​uiner-Mathieu–Semenov–Zainoulline conjecture. The remaining components do not change after generic splitting of AA:

ji=(ji)FAfor i=2,…,r.j_i=(j_i)_{F_A}\qquad\text{for }i=2,\ldots,r.

The first component is known to vanish after splitting AA; the conjecture asserts that all the other components are already unchanged by this generic splitting. The source gives no resolution, so the conjecture is recorded as open.

References

Primary source

Maksim Zhykhovich, “The J-invariant over splitting fields of Tits algebras”, arXiv:2205.02819 (2023).

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