Back to Search Start Over

Uncountable classical and quantum complexity classes

Authors :
Abuzer Yakaryilmaz
Maksims Dimitrijevs
Source :
RAIRO - Theoretical Informatics and Applications. 52:111-126
Publication Year :
2018
Publisher :
EDP Sciences, 2018.

Abstract

It is known that poly-time constant-space quantum Turing machines (QTMs) and logarithmic-space probabilistic Turing machines (PTMs) recognize uncountably many languages with bounded error (A.C. Cem Say and A. Yakaryılmaz, Magic coins are useful for small-space quantum machines. Quant. Inf. Comput. 17 (2017) 1027–1043). In this paper, we investigate more restricted cases for both models to recognize uncountably many languages with bounded error. We show that double logarithmic space is enough for PTMs on unary languages in sweeping reading mode or logarithmic space for one-way head. On unary languages, for quantum models, we obtain middle logarithmic space for counter machines. For binary languages, arbitrary small non-constant space is enough for PTMs even using only counter as memory. For counter machines, when restricted to polynomial time, we can obtain the same result for linear space. For constant-space QTMs, we obtain the result for a restricted sweeping head, known as restarting realtime.

Details

ISSN :
1290385X and 09883754
Volume :
52
Database :
OpenAIRE
Journal :
RAIRO - Theoretical Informatics and Applications
Accession number :
edsair.doi...........b84893313e0dfd591531f9d18639adbe
Full Text :
https://doi.org/10.1051/ita/2018012