title: CENTER PROBLEM FOR A THIRD-ORDER ODES.
abstract: We obtain necessary and sufficient conditions for the existence of a center on a local center manifold for three 4-parameter families of quadratic systems on ℝ3. We also give a positive answer to an open question posed in [Dias & Mello(2010)] related to similar systems.
authors.affiliation: North Carolina State University, Raleigh, NC, 27695, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Mahdi
keywords: center manifold; center-focus problem; first integral