  The dimensional-deconstruction prescription of Arkani-Hamed, Cohen, Kaplan,
Karch and Motl provides a mechanism for recovering the $A$-type (2,0) theories
on $T^2$, starting from a four-dimensional $\mathcal N=2$ circular-quiver
theory. We put this conjecture to the test using two exact-counting arguments:
In the decompactification limit, we compare the Higgs-branch Hilbert series of
the 4D $\mathcal N=2$ quiver to the "half-BPS" limit of the (2,0)
superconformal index. We also compare the full partition function for the 4D
quiver on $S^4$ to the (2,0) partition function on $S^4 \times T^2$. In both
cases we find exact agreement. The partition function calculation sets up a
dictionary between exact results in 4D and 6D.
