  We illustrated via the sunset diagram that dimensional regularization
'deforms' the nonlocal contents of multi-loop diagrams with its equivalence to
cut-off regularization scheme recovered only after sub-divergence were
subtracted. Then we employed a differential equation approach for calculating
loop diagrams to verify that dimensional regularization deformed the 'low
energy' contents before subtraction. The virtues of the differential equation
approach were argued especially in non-perturbative perspective.
