Bass conjecture

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In mathematics, especially algebraic geometry, the Bass conjecture says that certain algebraic K-groups are supposed to be finitely generated. The conjecture was proposed by Hyman Bass.

Statement of the conjecture[edit]

Any of the following equivalent statements is referred to as the Bass conjecture.

  • For any finitely generated Z-algebra A, the groups K'n(A) are finitely generated (K-theory of finitely generated A-modules, also known as G-theory of A) for all n ≥ 0.
  • For any finitely generated Z-algebra A, that is a regular ring, the groups Kn(A) are finitely generated (K-theory of finitely generated locally free A-modules).
  • For any scheme X of finite type over Spec(Z), K'n(X) is finitely generated.
  • For any regular scheme X of finite type over Z, Kn(X) is finitely generated.

The equivalence of these statements follows from the agreement of K- and K'-theory for regular rings and the localization sequence for K'-theory.

Known cases[edit]

Daniel Quillen showed that the Bass conjecture holds for all (regular, depending on the version of the conjecture) rings or schemes of dimension ≤ 1, i.e., algebraic curves over finite fields and the spectrum of the ring of integers in a number field.

The (non-regular) ring A = Z[x, y]/x2 has an infinitely generated K1(A).

Implications[edit]

The Bass conjecture is known to imply the Beilinson–Soulé vanishing conjecture.[1]

References[edit]

  1. ^ Kahn, Bruno (2005), "Algebraic K-theory, algebraic cycles and arithmetic geometry", in Friedlander, Eric; Grayson, Daniel, Handbook of Algebraic K-theory, Berlin, New York: Springer-Verlag, pp. 351–428, doi:10.1007/3-540-27855-9_9 , Theorem 39