Gary R. Nicklason
Abstract:
We consider center conditions for plane polynomial systems of Abel type
consisting of a linear center perturbed by the sum of 2 homogeneous
polynomials of degrees n and 2n-1 where
.
Using properties of Abel equations we obtain two general systems valid
for arbitrary values on n. For the cubic n=2 systems we find several
sets of new center conditions, some of which show that the results in a
paper by Hill, Lloyd and Pearson which were conjectured to be complete are
in fact not complete. We also present a particular system which appears to
be a counterexample to a conjecture by Zoladek et al. regarding
rational reversibility in cubic polynomial systems.
Submitted March 30, 2015. Published July 16, 2015.
Math Subject Classifications: 34A05, 34C25.
Key Words: Center-focus problem; Abel differential equation; constant invariant;
symmetric centers.
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Gary R. Nicklason Mathematics, Physics and Geology Cape Breton University Sydney, Nova Scotia, B1P 6L2, Canada email: gary_nicklason@cbu.ca |
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