Frobenius and homological dimensions of complexes

• Autores: Taran Funk, Thomas Marley
• Localización: Collectanea mathematica, ISSN 0010-0757, Vol. 71, Fasc. 2, 2020, págs. 287-297
• Idioma: inglés
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• Resumen

  • It is proved that a module M over a Noetherian local ring R of prime characteristic and positive dimension has finite flat dimension if TorRi(eR,M)=0 for dimR consecutive positive values of i and infinitely many e. Here eR denotes the ring R viewed as an R-module via the eth iteration of the Frobenius endomorphism. In the case R is Cohen–Macualay, it suffices that the Tor vanishing above holds for a single e⩾logpe(R), where e(R) is the multiplicity of the ring. This improves a result of Dailey et al. (J Commut Algebra), as well as generalizing a theorem due to Miller (Contemp Math 331:207–234, 2003) from finitely generated modules to arbitrary modules. We also show that if R is a complete intersection ring then the vanishing of TorRi(eR,M) for single positive values of i and e is sufficient to imply M has finite flat dimension. This extends a result of Avramov and Miller (Math Res Lett 8(1–2):225–232, 2001).