Laurent powers of a transcendental element are linearly independent
ProvedIntegerWindingExponentialIndependence.laurentPowersLinearIndependentLet E/K be any field extension and let z ∈ E be transcendental over K. Then the two-sided family (zⁿ) indexed by all integers n is linearly independent over K. Negative exponents are included, so this is a Laurent-polynomial statement rather than only an ordinary-polynomial statement.
import Definitions.Def_IntegerWindingExponentialIndependence_CoreV1 import Mathlib.Algebra.Polynomial.Laurent import Mathlib.LinearAlgebra.Finsupp.VectorSpace set_option autoImplicit false
namespace IntegerWindingExponentialIndependence
theorem laurentPowersLinearIndependent
{K E : Type*} [Field K] [Field E] [Algebra K E]
{z : E} (hz : Transcendental K z) :
LinearIndependent K (fun n : ℤ => z ^ n) := by sorry
end IntegerWindingExponentialIndependenceRead-back
What the Lean code literally says, in plain math · gpt-5.6-sol
For any universe-polymorphic types and , equipped respectively with field structures and with an algebra structure of over , and for any that is transcendental over , the family , using integer powers and hence both positive and negative powers, is linearly independent over . Explicitly, every finitely supported family of coefficients satisfying in has every . There is no finiteness or finite-dimensionality assumption on either field extension. No separate hypothesis is stated; the transcendence hypothesis excludes , since is algebraic. For field extensions in which no transcendental element exists, there is no satisfying the hypothesis, so the theorem has no applicable instance.
Confirmed by the mission captain (proposal self-audit).