Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Research › peer-review
On equations over sets of integers. / Jez, Artur; Okhotin, Alexander.
STACS 2010 - 27th International Symposium on Theoretical Aspects of Computer Science. 2010. p. 477-488 (Leibniz International Proceedings in Informatics, LIPIcs; Vol. 5).Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Research › peer-review
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TY - GEN
T1 - On equations over sets of integers
AU - Jez, Artur
AU - Okhotin, Alexander
PY - 2010
Y1 - 2010
N2 - Systems of equations with sets of integers as unknowns are considered. It is shown that the class of sets representable by unique solutions of equations using the operations of union and addition S + T = {m + n | m ∈ S, n ∈ T} and with ultimately periodic constants is exactly the class of hyper-arithmetical sets. Equations using addition only can represent every hyper-arithmetical set under a simple encoding. All hyper-arithmetical sets can also be represented by equations over sets of natural numbers equipped with union, addition and subtraction S - T = {m-n|m ∈ S,n ∈T,m≥ n}. Testing whether a given system has a solution is Σ1 1-complete for each model. These results, in particular, settle the expressive power of the most general types of language equations, as well as equations over subsets of free groups.
AB - Systems of equations with sets of integers as unknowns are considered. It is shown that the class of sets representable by unique solutions of equations using the operations of union and addition S + T = {m + n | m ∈ S, n ∈ T} and with ultimately periodic constants is exactly the class of hyper-arithmetical sets. Equations using addition only can represent every hyper-arithmetical set under a simple encoding. All hyper-arithmetical sets can also be represented by equations over sets of natural numbers equipped with union, addition and subtraction S - T = {m-n|m ∈ S,n ∈T,m≥ n}. Testing whether a given system has a solution is Σ1 1-complete for each model. These results, in particular, settle the expressive power of the most general types of language equations, as well as equations over subsets of free groups.
KW - Arithmetical hierarchy
KW - Computability
KW - Hyper-arithmetical hierarchy
KW - Language equations
UR - http://www.scopus.com/inward/record.url?scp=84880277687&partnerID=8YFLogxK
U2 - 10.4230/LIPIcs.STACS.2010.2478
DO - 10.4230/LIPIcs.STACS.2010.2478
M3 - Conference contribution
AN - SCOPUS:84880277687
SN - 9783939897163
T3 - Leibniz International Proceedings in Informatics, LIPIcs
SP - 477
EP - 488
BT - STACS 2010 - 27th International Symposium on Theoretical Aspects of Computer Science
T2 - 27th International Symposium on Theoretical Aspects of Computer Science, STACS 2010
Y2 - 4 March 2010 through 6 March 2010
ER -
ID: 78935862