Solution of a problem of Z. Daróczy,J. Jarczyk and W. Jarczyk and generalization of a theorem of R. Ger and T. Kochane

We generalize a theorem proved by R. Ger and T. Kochanek [4]. Hence we obtain the solution of a problem posed by Z. Daróczy, J. Jarczyk and W. Jarczyk [2].     

On A. Lino, W. Demelo and C. C. Pugh''''s Conjecture (Part 1)

For Lienard's equation or its equivalent system (?)=y-F(x),(?)=-x,(F(x)=integral from n=0 to x (f(ξ)dξ)). (*) there were quite a few papers studied (*) to have some limit cycles. Although there were few papers studied (*) to have at most m limit cycles, but good results were given already. A. Lino, W. Demelo and C. C. Pugh conjectured following fact: when f(x)=sum from N (a_ix~i) (N=2n+1,2n+2),system (*) has at most n limit cycles.