Predictive recursion and computational complexity
Predictive recursion and computational complexity
A new recursion-theoretic characterization of the polytime functions
Computational Complexity
LOGSPACE and PTIME characterized by programming languages
Theoretical Computer Science - Special issue on mathematical foundations of programming semantics
Linear Time Simulation of Multihead Turing Machines with Head-to-Head Jumps
Proceedings of the Fourth Colloquium on Automata, Languages and Programming
Subsequential Functions: Characterizations, Minimization, Examples
Proceedings of the 6th International Meeting of Young Computer Scientists on Aspects and Prospects of Theoretical Computer Science
Automata and Coinduction (An Exercise in Coalgebra)
CONCUR '98 Proceedings of the 9th International Conference on Concurrency Theory
Ramified Recurrence and Computational Complexity II: Substitution and Poly-Space
CSL '94 Selected Papers from the 8th International Workshop on Computer Science Logic
Automatic Sequences: Theory, Applications, Generalizations
Automatic Sequences: Theory, Applications, Generalizations
A characterization of log-space computable functions
ACM SIGACT News
Neat function algebraic characterizations of logspace and linspace
Computational Complexity
Stratified Bounded Affine Logic for Logarithmic Space
LICS '07 Proceedings of the 22nd Annual IEEE Symposium on Logic in Computer Science
Global and local space properties of stream programs
FOPARA'09 Proceedings of the First international conference on Foundational and practical aspects of resource analysis
Feasible functions over co-inductive data
WoLLIC'10 Proceedings of the 17th international conference on Logic, language, information and computation
Some programming languages for LOGSPACE and PTIME
AMAST'06 Proceedings of the 11th international conference on Algebraic Methodology and Software Technology
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Ramified recurrence over free algebras has been used over the last two decades to provide machine-independent characterizations of major complexity classes. We consider here ramification for the dual setting, referring to coinductive data and corecurrence rather than inductive data and recurrence. Whereas ramified recurrence is related basically to feasible time (PTime) complexity, we show here that ramified corecurrence is related fundamentally to feasible space. Indeed, the 2-tier ramified corecursive functions are precisely the functions over streams computable in logarithmic space. Here we define the complexity of computing over streams in terms of the output rather than the input, i.e. the complexity of computing the n-th entry of the output as a function of n. The class of stream functions computable in logspace seems to be of independent interest, both theoretical and practical. We show that a stream function is definable by ramified corecurrence in two tiers iff it is computable by a transducer on streams that operates in space logarithmic in the position of the output symbol being computed. A consequence is that the two-tier ramified corecursive functions over finite streams are precisely the logspace functions, in the usual sense.