A note on decision problems for three-way two-dimensional finite automata

1980 ◽  
Vol 10 (4-5) ◽  
pp. 245-248 ◽  
Author(s):  
Katsushi Inoue ◽  
Itsuo Takanami
1991 ◽  
Vol 15 (1) ◽  
pp. 90-98
Author(s):  
Juraj Hromkovič ◽  
Katsushi Inoue ◽  
Akira Ito ◽  
Itsuo Takanami

It is well known that four-way two-dimensional alternating finite automata are more powerful than three-way two-dimensional alternating finite automata, which are more powerful than two-way two-dimensional alternating finite automata. This paper shows that four-way, three-way, and two-way two-dimensional “synchronized” alternating finite automata all have the same power as rectangular array bounded automata.


2013 ◽  
Vol 123 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Paul C. Bell ◽  
Vesa Halava ◽  
Mika Hirvensalo

2020 ◽  
Vol 31 (04) ◽  
pp. 527-538
Author(s):  
Grzegorz Madejski ◽  
Andrzej Szepietowski

Two-dimensional general row jumping finite automata were recently introduced as an interesting computational model for accepting two-dimensional languages. These automata are nondeterministic. They guess an order in which rows of the input array are read and they jump to the next row only after reading all symbols in the previous row. In each row, they choose, also nondeterministically, an order in which segments of the row are read. In this paper, we study the membership problem for these automata. We show that each general row jumping finite automaton can be simulated by a nondeterministic Turing machine with space bounded by the logarithm. This means that the fixed membership problems for such automata are in NL, and so in P. On the other hand, we show that the uniform membership problem is NP-complete.


Author(s):  
KATSUSHI INOUE ◽  
ITSUO SAKURAMOTO ◽  
MAKOTO SAKAMOTO ◽  
ITSUO TAKANAMI

This paper deals with two topics concerning two-dimensional automata operating in parallel. We first investigate a relationship between the accepting powers of two-dimensional alternating finite automata (2-AFAs) and nondeterministic bottom-up pyramid cellular acceptors (NUPCAs), and show that Ω ( diameter × log diameter ) time is necessary for NUPCAs to simulate 2-AFAs. We then investigate space complexity of two-dimensional alternating Turing machines (2-ATMs) operating in small space, and show that if L (n) is a two-dimensionally space-constructible function such that lim n → ∞ L (n)/ loglog n > 1 and L (n) ≤ log n, and L′ (n) is a function satisfying L′ (n) =o (L(n)), then there exists a set accepted by some strongly L (n) space-bounded two-dimensional deterministic Turing machine, but not accepted by any weakly L′ (n) space-bounded 2-ATM, and thus there exists a rich space hierarchy for weakly S (n) space-bounded 2-ATMs with loglog n ≤ S (n) ≤ log n.


Author(s):  
Serge Miguet ◽  
Annick Montanvert ◽  
P. S. P. Wang

Several nonclosure properties of each class of sets accepted by two-dimensional alternating one-marker automata, alternating one-marker automata with only universal states, nondeterministic one-marker automata, deterministic one-marker automata, alternating finite automata, and alternating finite automata with only universal states are shown. To do this, we first establish the upper bounds of the working space used by "three-way" alternating Turing machines with only universal states to simulate those "four-way" non-storage machines. These bounds provide us a simplified and unified proof method for the whole variants of one-marker and/or alternating finite state machine, without directly analyzing the complex behavior of the individual four-way machine on two-dimensional rectangular input tapes. We also summarize the known closure properties including Boolean closures for all the variants of two-dimensional alternating one-marker automata.


Author(s):  
KATSUSHI INOUE ◽  
ITSUO TAKANAMI

This paper first shows that REC, the family of recognizable picture languages in Giammarresi and Restivo,3 is equal to the family of picture languages accepted by two-dimensional on-line tessellation acceptors in Inoue and Nakamura.5 By using this result, we then solve open problems in Giammarresi and Restivo,3 and show that (i) REC is not closed under complementation, and (ii) REC properly contains the family of picture languages accepted by two-dimensional nondeterministic finite automata even over a one letter alphabet.


1979 ◽  
Vol 7 (3) ◽  
pp. 207-213 ◽  
Author(s):  
Katsushi Inoue ◽  
Akira Nakamura

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