Future temporal logic needs infinitely many modalities.

Yoram Hirshfeld Alexander Moshe Rabinovich Future temporal logic needs infinitely many modalities. 196-208 2003 187 Inf. Comput. 2 http://dx.doi.org/10.1016/S0890-5401(03)00163-9 db/journals/iandc/iandc187.html#HirshfeldR03