If x1 x1(z) with ROC = R1 and x2 x2(z) with ROC = R2 then ROC for x1 + x2 will be __________ (where Ri → Region of convergence and x1 and x2 are causal).

If x₁[n]  x₁(z) with ROC = R₁ and x₂[n]  x₂(z) with ROC = R₂ then ROC for x₁[n] + x₂[n] will be __________ (where R_i → Region of convergence and x₁[n] and x₂[n] are causal).