pow
The lemma shows that if a real number x lies in the subfield generated by φ, then any natural power x^n also lies in that subfield. Analysts working with algebraic closures in Recognition Science models cite this result when propagating phi-closure through polynomial expressions. The proof reduces immediately to the built-in pow_mem property of the Subfield instance for phiSubfield φ.
claimIf $x$ belongs to the subfield of $ℝ$ generated by $φ$, then for every natural number $n$, $x^n$ also belongs to that subfield.
background
In the RecogSpec.Core module, phiSubfield φ is defined as the smallest subfield of the reals containing φ, obtained by closing the singleton set {φ} under field operations. PhiClosed φ x is the proposition that x lies in this subfield. This setup supports algebraic manipulations involving the golden ratio φ in the Recognition Science framework, where φ appears as the self-similar fixed point (T6).
proof idea
The proof is a one-line wrapper that invokes the pow_mem lemma from the Subfield structure on (phiSubfield φ), applied to the hypothesis hx and the exponent n, with simpa handling the simplification.
why it matters in Recognition Science
This closure property under natural powers feeds into downstream results such as energy_conservation in Action.Hamiltonian and various ODE uniqueness theorems in Cost.AczelProof, Cost.AczelTheorem, and Foundation.DAlembert.AnalyticBridge. It ensures that powers of phi-closed quantities remain within the algebraic structure generated by φ, supporting the phi-ladder and mass formulas in the Recognition Science chain (T5-T6).
scope and limits
- Does not establish closure under arbitrary real exponents.
- Does not specify the value of φ or its minimal polynomial.
- Does not address closure under addition or multiplication explicitly (though inherited from subfield).
- Does not apply outside the reals.
formal statement (Lean)
96lemma pow (hx : PhiClosed φ x) (n : ℕ) : PhiClosed φ (x ^ n) := by
proof body
One-line wrapper that applies simpa.
97 simpa using (phiSubfield φ).pow_mem hx n
98
used by (25)
-
energy_conservation -
ode_neg_zero_uniqueness -
ode_neg_zero_uniqueness -
aczel_classification_conditional -
ode_neg_zero_uniqueness -
hyperbolic_ode_unique -
coerciveL2Bound_of_tailFluxVanish -
ancientDecay_implies_A2_integrable -
ancientDecay_implies_Aprime2r2_integrable -
operatorPairing_of_decayFull -
sobolev_H1_half_line_decay -
hasDerivAt_rpow_two -
pow_self -
differentiableAt_coordRay_i_sq -
differentiableAt_coordRay_partialDeriv_v2_radialInv -
differentiableAt_coordRay_radialInv -
partialDeriv_v2_radialInv -
partialDeriv_v2_spatialRadius -
secondDeriv_radialInv -
differentiableAt_coordRay_partialDeriv_v2_radialInv_proved -
partialDeriv_v2_radialInv_proved -
secondDeriv_radialInv_proved -
pow10 -
alphaInvValueStr -
pow10