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A Counterexample to a Proposed Solution of Hilbert's Sixteenth Problem for Quadratic Systems
Author(s) -
Songling Shi
Publication year - 1988
Publication title -
bulletin of the london mathematical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.396
H-Index - 48
eISSN - 1469-2120
pISSN - 0024-6093
DOI - 10.1112/blms/20.6.597
Subject(s) - counterexample , mathematics , limit (mathematics) , quadratic equation , plane (geometry) , field (mathematics) , pure mathematics , mathematical analysis , discrete mathematics , geometry
We give a counterexample to two results used by Professor Qin Yuanxun in his published proof that a quadratic vector field in the plane has at most four limit cycles.