例句與造句

1. These polynomial vector fields were studied by Poincar? who had the idea of abandoning the search for finding exact solutions to the system, and instead attempted to study the qualitative features of the collection of all possible solutions.
2. A simple concept is that of a "'polynomial vector field "', in other words a vector field expressed with respect to a standard co-ordinate basis as the first partial derivatives with polynomial coefficients.
3. The second part of Hilbert's 16th problem is to decide an upper bound for the number of limit cycles in polynomial vector fields of degree " n " and, similar to the first part, investigate their relative positions.
4. The question whether there exists a finite upper bound " H " ( " n " ) for the number of limit cycles of planar polynomial vector fields of degree " n " remains unsolved for any " n " > 1 . ( " H " ( 1 ) = 0 since linear vector fields do not have limit cycles . ) Evgenii Landis and Ivan Petrovsky claimed a solution in the 1950s, but it was shown wrong in the early 1960s.
5. It's difficult to find polynomial vector field in a sentence. 用polynomial vector field造句挺難的