Given a formal map F=(F1β...,Fnβ) of the form z+higher order
terms, we give tree expansion formulas and associated algorithms for the D-Log
of F and the formal flow F_t. The coefficients which appear in these formulas
can be viewed as certain generalizations of the Bernoulli numbers and the
Bernoulli polynomials. Moreover the coefficient polynomials in the formal flow
formula coincide with the strict order polynomials in combinatorics for the
partially ordered sets induced by trees. Applications of these formulas to the
Jacobian Conjecture are discussed.Comment: Latex, 32 page