Abstract
Abstract
Let
$({\cal{A}},{\cal{E}})$
be an exact category. We establish basic results that allow one to identify sub(bi)functors of
${\operatorname{Ext}}_{\cal{E}}(-,-)$
using additivity of numerical functions and restriction to subcategories. We also study a small number of these new functors over commutative local rings in detail and find a range of applications from detecting regularity to understanding Ulrich modules.
Publisher
Cambridge University Press (CUP)