Past exam of the mathematics course of the University of Cambridge 2025 iii Paper 166 2 e Solution Created 2026-09-24 Updated 2026-09-24
Write for the polynomial length. The height bound for a polynomial evaluation isprovided the denominator is nonzero. At non-Archimedean places the integral coefficients and ultrametric inequality give the local estimate without an extra constant; at Archimedean places the triangle inequality gives the polynomial length. Multiplication over every place of a number field and the product formula produce the displayed bound.
Past exam of the mathematics course of the University of Cambridge 2026 iii Paper 166 2 b Solution Created 2026-09-24 Updated 2026-09-24
Choose a number field containing . At every place of , putThe triangle inequality giveswhere at every non-Archimedean place because the coefficients are integers, while at an Archimedean place one may takeRaise these inequalities to the local weights and multiply over all places. The definition of the Absolute multiplicative Weil height and the product formula then giveThis is the height bound for a polynomial evaluation.
Past exam of the mathematics course of the University of Cambridge 2026 iii Paper 166 2 c Solution Created 2026-09-24 Updated 2026-09-24
Take distinct . Their difference has the formwhere has degree at most and polynomial length at most . By the height bound for a polynomial evaluation,The algebraic number is nonzero and has degree at most , so the Liouville height inequality gives the separation
All elements of lie in an interval of length at mostSince , another application of the Liouville height inequality givesThe number of points in an interval is at most one plus its length divided by their minimum separation. ConsequentlyThus the requested statement holds, for example, with the absolute constant .