 Periods can be defined as complex numbers whose real and imaginary parts are values of absolutely convergent integrals of rational functions with rational coefficients, over domains in formula_1 given by polynomial inequalities with rational coefficients .The coefficients of the rational functions and polynomials can be generalised to algebraic numbers since integrals and irrational algebraic numbers are expressible in terms of areas of suitable domains.Besides the algebraic numbers, the following numbers are known to be periods