string ring_of_differential_operators This command is used to define a ring of differential operators with the macros define_ring, weight_vector and elimination_order. The user cannot use the variable names h, e, H and E. cf. show_ring, system_variable --- CurrentRing print_switch_status, switch_function Example: [(x,y) ring_of_differential_operators [[(Dx) 1 (Dy) 1]] weight_vector 0] define_ring Define the ring of differential operators Q<x,y,Dx,Dy> with the order obtained by refining the partial order defined by the weight vector [x,y,Dx,Dy] = [0,0,1,1] Example: [(x,y) ring_of_differential_operators 0 [(weightedHomogenization) 1]] define_ring Example: [(x,y) ring_of_differential_operators [[(x) -1 (Dx) 1]] weight_vector 0 [(degreeShift) [[1 0 1]]] ] define_ring Example: [(x,y,z) ring_of_differential_operators (Dx,Dy) elimination_order 0] define_ring Dx,Dy, and Dz are corresponding differential operators to the space variables x, y and z.

Nobuki Takayama 平成17年2月10日