Abstract
We focus our attention onto polynomial-time sub-linear-space computation for decision problems, which are parameterized by size parameters m(x), where the informal term “sub linear” means a function of the form \(m(x)^{\varepsilon }\cdot polylog(|x|)\) on input instances x for a certain absolute constant \(\varepsilon \in (0,1)\) and a certain polylogarithmic function polylog(n). The parameterized complexity class \(\mathrm {PsubLIN}\) consists of all parameterized decision problems solvable simultaneously in polynomial time using sub-linear space. This complexity class is associated with the linear space hypothesis. There is no known inclusion relationships between \(\mathrm {PsubLIN}\) and \(\mathrm {para}\text {-}\,\!\mathrm {NL}\), where the prefix “para-” indicates the natural parameterization of a given complexity class. Toward circumstantial evidences for the inclusions and separations of the associated complexity classes, we seek their relativizations. However, the standard relativization of Turing machines is known to violate the relationships of \(\mathrm {L}\subseteq \mathrm {NL}=\mathrm {co}\text {-}\,\!\mathrm {NL}\subseteq \mathrm {DSPACE}[O(\log ^2{n})]\cap \mathrm {P}\). We instead consider special oracles, called \(\mathrm {NL}\)-supportive oracles, which guarantee these relationships in the corresponding relativized worlds. This paper vigorously constructs such NL-supportive oracles that generate relativized worlds where, for example, \(\mathrm {para}\text {-}\,\!\mathrm {L}\ne \mathrm {para}\text {-}\,\!\mathrm {NL}\nsubseteq \mathrm {PsubLIN}\) and \(\mathrm {para}\text {-}\,\!\mathrm {L}\ne \mathrm {para}\text {-}\,\!\mathrm {NL}\subseteq \mathrm {PsubLIN}\).
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Notes
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A tape is write only if a tape head must move to the right whenever it writes any non-blank symbol.
References
Baker, T., Gill, J., Solovay, R.: Relativizations of the P=?NP question. SIAM J. Comput. 4, 431–442 (1975)
Barnes, G., Buss, J.F., Ruzzo, W.L., Schieber, B.: A sublinear space, polynomial time algorithm for directed s-t connectivity. SIAM J. Comput. 27, 1273–1282 (1998)
Immerman, N.: Nondeterministic space is closed under complement. SIAM J. Comput. 17, 935–938 (1988)
Kirsig, B., Lange, K.J.: Separation with the Ruzzo, Simon, and Tompa relativization implies DSPACE[\(\log {n}\)] \(\ne \) NSPACE[\(\log {n}\)]. Inf. Process. Lett. 25, 13–15 (1987)
Ladner, R.E., Lynch, N.A.: Relativization of questions about log space computability. Math. Syst. Theory 10, 19–32 (1976)
Reingold, O.: Undirected connectivity in log-space. J. ACM 55 (2008). Article 17 (24 pages)
Ruzzo, W.L., Simon, J., Tompa, M.: Space-bounded hierarchies and probabilistic computations. J. Comput. Syst. Sci. 28, 216–230 (1984)
Savitch, W.J.: Relationships between nondeterministic and deterministic tape complexities. J. Comput. Syst. Sci. 4, 177–192 (1970)
Szelepcsényi, R.: The method of forced enumeration for nondeterministic automata. Acta Informatica 26, 279–284 (1988)
Yamakami, T.: Parameterized graph connectivity and polynomial-time sub-linear-space short reductions. In: Hague, M., Potapov, I. (eds.) RP 2017. LNCS, vol. 10506, pp. 176–191. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-67089-8_13
Yamakami, T.: The 2CNF Boolean formula satisfiability problem and the linear space hypothesis. In: Proceedings of MFCS 2017. LIPIcs, vol. 83, pp. 62:1–62:14. Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik (2017). A complete version is found at arXiv:1709.10453
Yamakami, T.: State complexity characterizations of parameterized degree-bounded graph connectivity, sub-linear space computation, and the linear space hypothesis. In: Konstantinidis, S., Pighizzini, G. (eds.) DCFS 2018. LNCS, vol. 10952, pp. 237–249. Springer, Cham (2018). https://doi.org/10.1007/978-3-319-94631-3_20. A complete and corrected version is found at arXiv:1811.06336
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Yamakami, T. (2019). Supportive Oracles for Parameterized Polynomial-Time Sub-Linear-Space Computations in Relation to L, NL, and P. In: Gopal, T., Watada, J. (eds) Theory and Applications of Models of Computation. TAMC 2019. Lecture Notes in Computer Science(), vol 11436. Springer, Cham. https://doi.org/10.1007/978-3-030-14812-6_41
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