In this paper,the F-equivariant (s,t)-equivalence relation and F-equivariant infinitesimally (r,s)-stability of F-equivariant bifurcation problem are defined. T
<正>In 2000,Wu presented two new types of generalized Ball curves,one of which is called an NB1 curve located between the Wang Ball curve and the Said Ball curv
Characteristic finite difference fractional step schemes are put forward. The electric Potential equation is described by a seven-point finite difference scheme