Characterization and computation of ancestors in reaction systems
In reaction systems, preimages and n th ancestors are sets of reactants leading to the production of a target set of products in either 1 or n steps, respectively. Many computational problems on preimages and ancestors, such as finding all minimum-cardinality n th ancestors, computing their size or...
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Published in | Soft computing (Berlin, Germany) Vol. 25; no. 3; pp. 1683 - 1698 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Berlin/Heidelberg
Springer Berlin Heidelberg
01.02.2021
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Subjects | |
Online Access | Get full text |
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Summary: | In reaction systems, preimages and
n
th ancestors are sets of reactants leading to the production of a target set of products in either 1 or
n
steps, respectively. Many computational problems on preimages and ancestors, such as finding all minimum-cardinality
n
th ancestors, computing their size or counting them, are intractable. In this paper, we characterize all
n
th ancestors using a Boolean formula that can be computed in polynomial time. Once simplified, this formula can be exploited to easily solve all preimage and ancestor problems. This allows us to directly relate the difficulty of ancestor problems to the cost of the simplification so that new insights into computational complexity investigations can be achieved. In particular, we focus on two problems: (i) deciding whether a preimage/
n
th ancestor exists and (ii) finding a preimage/
n
th ancestor of minimal size. Our approach is constructive, it aims at finding classes of reactions systems for which the ancestor problems can be solved in polynomial time, in exact or approximate way. |
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ISSN: | 1432-7643 1433-7479 |
DOI: | 10.1007/s00500-020-05300-0 |