[tex]\sum_{n=0}^{\infty}\frac{a(n)g^{n}}{\epsilon^{n}}[/tex]

where g is the coupling constant of our theory..then let,s suppose this series is summable and that we can get the correct result S

[tex]S=S(g,\epsilon)[/tex] then let,s suppose that S have a singularity at

[tex]\epsilon=0[/tex] my question is how we could remove this singularity by renormalization methods....thanks.