Tensor weight structures and t-structures on derived categories of Noetherian schemes

TL;DR

This paper characterizes certain weight structures on derived categories of Noetherian schemes, linking them to Thomason filtrations, and classifies these structures explicitly for the projective line.

Contribution

It establishes a bijection between $ ensor^c$-weight structures and Thomason filtrations, extending the classification of tensor t-structures to weight structures on derived categories.

Findings

Bijection between $ ensor^c$-weight structures and Thomason filtrations.

Classification of tensor weight structures on the derived category of the projective line.

No non-trivial tensor weight structures on the bounded derived category of coherent sheaves on $P^1_k$.

Abstract

We give a condition which characterises those weight structures on a derived category which come from a Thomason filtration on the underlying scheme. Weight structures satisfying our condition will be called $\otimes ^c$-weight structures. More precisely, for a Noetherian separated scheme $X$, we give a bijection between the set of compactly generated $\otimes ^c$-weight structures on $\mathbf{D} (\mathrm{Qcoh\hspace{1mm}}X)$ and the set of Thomason filtrations of $X$. We achieve this classification in two steps. First, we show that the bijection of S\v{t}ov\'{\i}\v{c}ek and Posp\'{\i}\v{s}il restricts to give a bijection between the set of compactly generated $\otimes ^c$-weight structures and the set of compactly generated tensor t-structures. We then use our earlier classification of compactly generated tensor t-structures to obtain the desired result. We also study some immediate consequences of these classifications in the particular case of the projective line. We show that in contrast to the case of tensor t-structures, there are no non-trivial tensor weight structures on $\mathbf{D}^b (\mathrm{Coh \hspace{1mm}} \mathbb{P}^1_k)$.