Feng, Li; Yirong, Liu; Hongwei, Li - In: Mathematics and Computers in Simulation (MATCOM) 81 (2011) 12, pp. 2595-2607
In this paper, center conditions and bifurcation of limit cycles at the nilpotent critical point in a class of septic polynomial differential systems are investigated. With the help of computer algebra system MATHEMATICA, the first 13 quasi-Lyapunov constants are deduced. As a result, sufficient...
