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phi_sq_identity

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The golden ratio satisfies the algebraic relation φ² = φ + 1. Number theorists cataloguing RS identities and linguists constructing lexicon ratio certificates cite this fact directly. The proof is a one-line wrapper that reuses the phi_sq_eq lemma from the constants module.

claimThe golden ratio φ satisfies φ² = φ + 1.

background

The Number Theory from RS module catalogues five canonical identities, the second of which is the algebraic property of the golden ratio. This identity originates from the quadratic equation x² - x - 1 = 0 whose positive root defines φ. Upstream lemmas in Constants and PhiLadderLattice establish the same relation by explicit computation with the square root of five.

proof idea

The declaration is a one-line wrapper that applies the phi_sq_eq lemma imported from IndisputableMonolith.Constants.

why it matters in Recognition Science

This identity is the second of the five canonical RS number-theoretic identities listed in the module documentation. It supplies the phi_sq field in numberTheoryCert and the phi_sq_identity clause in the LexiconRatioCert structure. In the Recognition framework it encodes the self-similar fixed point of the J-function on the phi ladder.

scope and limits

formal statement (Lean)

  31theorem phi_sq_identity : phi ^ 2 = phi + 1 := phi_sq_eq

proof body

Term-mode proof.

  32
  33/-- φ^5 = 5φ+3 (Fibonacci). -/

used by (4)

From the project-wide theorem graph. These declarations reference this one in their body.

depends on (2)

Lean names referenced from this declaration's body.