A tilted heart is the abelian category obtained by changing a bounded t-structure using a
torsion pair in its heart. For a torsion pair in
, one has
and every object has a short exact
sequence with a torsion subobject in
and quotient in
. The tilt is the extension closure
. Its objects have cohomology
in degrees
,
respectively in
and
.
For coherent sheaves on a polarized threefold, the first slope tilt puts all strictly positive Harder-Narasimhan slopes in and all nonpositive slopes in
. A second tilt uses the tilt slope on this new heart. The
strict-positive/nonpositive boundary convention matters for the resulting double-tilt
heart used in large-volume stability.