LOGCFL

Template:Short description Template:Use list-defined references Template:Use dmy dates 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.Template:R This class is closed under complementation.Template:R It is situated between NL and AC¹, in the sense that it contains the formerTemplate:R and is contained in the latter.Template:R Problems that are complete for LOGCFL include many problems that can be characterized by acyclic hypergraphs:

• evaluating acyclic Boolean conjunctive queriesTemplate:R
• checking the existence of a homomorphism between two acyclic relational structuresTemplate:R
• checking the existence of solutions of acyclic constraint satisfaction problemsTemplate:R

LOGCFL is the set of decision problems solvable by nondeterministic auxiliary pushdown automata in log space and polynomial time.

See also

• List of complexity classes

External links

• Template:CZoo