In computational complexity theory, LOGCFL is the complexity class that contains all decision problems that can be reduced in logarithmic space to a context-free language. [1] This class is closed under complementation. [1] It is situated between NL and AC1, in the sense that it contains the former [1] and is contained in the latter. [2] Problems that are complete for LOGCFL include many problems that can be characterized by acyclic hypergraphs:
LOGCFL is the set of decision problems solvable by nondeterministic auxiliary pushdown automata in log space and polynomial time. [5]