The 
-Bass
conjecture asserts that the Hattori-Stallings
trace of every idempotent matrix over the
complex discrete group algebra of a discrete
group has finite support on conjugacy
classes of finite-order
elements. For 
,
write 
for the sum of its diagonal coefficients over 
. The conjectured conclusion is that a finite
set 
of such classes satisfies
 |
for every 
.
This is stronger than just vanishing on classes of elements of infinite order. Absolute summability of the trace coefficients
does not alone imply finite support.
