Solving two-variate polynomial identities

edit

Hi, some help is appreciated concerning the following search.

Suppose P1,P2,P3 are two-variate polynomials with integer coefficients in A,B. I'm searching for all sets (P1,P2,P3) such that:

i) P1(A,B)+P2(A,B)=P3(A,B)

ii) Greatest common denominator P1 and P2 equals 1 (Thus gcd( P1,P2 )=1)

iii) The product P1 * P2 * P3 can be divided by AB(A+B) (Thus gcd( P1.P2.P3, AB(A+B) )=AB(A+B))

Some well-known identities are A^2 + B(2A+B) = (A+B)^2, (B-A)^2 + 4AB = (A+B)^2 and (A+2B)A^3 + B(2A+3B)^3 = (A+B)(A+3B)^3. Most interesting are polynomials with only linear factors such as: 16(A+B)B^3 + A(3A+4B)^3+(A+2B)(3A+2B)^3 and 27(B-A)(A+B)^5 + (3A+2B)A^3(3A+5B)^2 = (2A+3B)B^3(5A+3B)^2.

I'm curious if via Sage one could develop a generating algorithm (maybe there is a connection to Graphs and/or Combinatorics ...). N.B.: A related question was raised earlier.

Thanks in advance for any support!

Roland