General lower bound for a linear form in logarithms Created 2026-09-24 Updated 2026-11-05
Choose logarithms of nonzero algebraic numbers and algebraic numbers , and put
Let be the naive polynomial height of the primitive algebraic minimal polynomial of . Choose and . There is an effectively computable , depending only on and the field extension degree of the number field generated by the data, such that
The algebraic constant term is included here. Theorem 1.1 of the primary Philippon–Waldschmidt paper bounds below by , with and . Our assumption absorbs the extra term into . Increasing each by a fixed power depending only on meets their normalization , with the change absorbed into . Thus this is a corollary of their general algebraic-coefficient theorem, including , rather than an application of only the homogeneous integer-coefficient bound.[ref]
Michel Waldschmidt 2026-11-05
A nonzero expression such as can be small, but lower bounds limit how small it can be in terms of the algebraic data and coefficient sizes. Such bounds convert qualitative nonvanishing into numerical restrictions useful in solving Diophantine equations. The algebraic-coefficient and integer-coefficient cases require distinct estimates.[ref]
Patrice Philippon 2026-11-05
Patrice Philippon works on transcendental number theory. His joint chapter with Michel Waldschmidt gives lower bounds for linear forms in logarithms of algebraic numbers, explicitly distinguishing general algebraic coefficients from rational-integer coefficients.[ref]
The central arithmetic question is quantitative: once a logarithmic combination is known to be nonzero, how closely can it approach zero? An explicit bound links Diophantine approximation to finite calculations and can help restrict candidate solutions of Diophantine equations.