1. A method, implemented through software operating in conjunction with computer hardware, for calculating a tax credit comprising: obtaining, implemented through software operating in conjunction with computer hardware, a tax function T(A); obtaining, implemented through software operating in conjunction with computer hardware, a value for a deduction D; obtaining, implemented through software operating in conjunction with computer hardware, a value for an income amount A at which a computation is based; obtaining, implemented through software operating in conjunction with computer hardware, a dampening factor k based on at least A and D; computing, implemented through software operating in conjunction with computer hardware, a tax credit C from at least one of: (a) non-recursively computing C=k(T(A)−T(A−(D−C))); (b) recursively computing C n+1 =k(T(A)−T(A−(D−C n ))); and returning, implemented through software operating in conjunction with computer hardware, a revalued deduction amount D−C for said non-recursive computing, and a revalued deduction amount D−C n+1 for said recursive computing.