R' at a point of {1+2a = 0}: nonzero
R' at a point of {1+a+b = 0}: nonzero
R' at a point of {1+2b = 0}: nonzero
R' at a point of {1+a+c = 0}: nonzero
R' at a point of {1+3a = 0}: nonzero
R' at a point of {1+2a+b = 0}: nonzero
R' at a point of {1+a+b+c = 0}: ZERO
multiplicity of the factor (1+a+b+c) in R' (along a transversal line): 1
