Exact quantum query complexity of $\rm{EXACT}_{k,l}^n$
  In the exact quantum query model a successful algorithm must always output the correct function value. We investigate the function that is true if exactly $k$ or $l$ of the $n$ input bits given by an oracle are 1. We find an optimal algorithm (for some cases), and a nontrivial general lower and upper bound on the minimum number of queries to the black box. 
Andris Ambainis, J\=anis Iraids, Daniel Nagaj
quant-ph cs.CC