Same as W[t], except that now the circuit depth can depend on the parameter k rather than being constant. (The number of unbounded-fanin gates along any path to the root is still at most t.)
W*[1] = W[1] [DFT96], and W*[2] = W[2] [DF97], but the problem is open for larger t.
A generalization of W[1].
The class of decision problems of the form (x,k) (k a parameter), that are fixed-parameter reducible to the following problem, for some constant h:
See W[1] for the definition of fixed-parameter reducibility.
Defined in [DF99].
Contained in W[SAT] and in W*[t].