GF0013

gaussian_ring_raw_multiply_commutative

Actual signed-coordinate Gaussian multiply is commutative by ordinary natural identities.

Alpha v34 checked-use · first admitted v30 · independently kernel and Lean verified; not Stable

Current library: Alpha v34, 4,223 checked-use theorems; Stable remains 432. Historical first admissions, original proof editions, and non-admitted aliases are preserved. Exact original first-admission records.

Inputs are genuine canonical signed-pair codes, not arbitrary naturals. Products start at the actual Gaussian identity, whose code is six. The factor list uses the proved prime-divisor property; irreducibility alone is not silently renamed primality. Uniqueness supplies equal lengths, a bounded bijection, and an actual unit at each match, including repeated factors. Units have empty factorizations and zero is excluded. Sorted primary representatives, Gaussian prime classification, and Eisenstein factorization are separate targets.

Exact theorem in conservative defined notation

∀ ap. ∀ an. ∀ bp. ∀ bn. ∀ cp. ∀ cn. ∀ dp. ∀ dn. ap · cp + an · cn + (bp · dn + bn · dp) + (cp · an + cn · ap + (dp · bp + dn · bn)) = cp · ap + cn · an + (dp · bn + dn · bp) + (ap · cn + an · cp + (bp · dp + bn · dn)) ∧ ap · dp + an · dn + (bp · cp + bn · cn) + (cp · bn + cn · bp + (dp · an + dn · ap)) = cp · bp + cn · bn + (dp · ap + dn · an) + (ap · dn + an · dp + (bp · cn + bn · cp))

Every linked abbreviation expands hygienically to the identical original native formula.

Definition DAG

none

Actual proof prerequisites

mul_comm · checked external prerequisiteadd_comm · checked external prerequisite
Original expanded first-order statement
forall ap an bp bn cp cn dp dn. (((((((((((ap) * (cp))) + (((an) * (cn))))) + (((((bp) * (dn))) + (((bn) * (dp))))))) + (((((((cp) * (an))) + (((cn) * (ap))))) + (((((dp) * (bp))) + (((dn) * (bn)))))))) = ((((((((cp) * (ap))) + (((cn) * (an))))) + (((((dp) * (bn))) + (((dn) * (bp))))))) + (((((((ap) * (cn))) + (((an) * (cp))))) + (((((bp) * (dp))) + (((bn) * (dn))))))))) /\ (((((((((ap) * (dp))) + (((an) * (dn))))) + (((((bp) * (cp))) + (((bn) * (cn))))))) + (((((((cp) * (bn))) + (((cn) * (bp))))) + (((((dp) * (an))) + (((dn) * (ap)))))))) = ((((((((cp) * (bp))) + (((cn) * (bn))))) + (((((dp) * (ap))) + (((dn) * (an))))))) + (((((((ap) * (dn))) + (((an) * (dp))))) + (((((bp) * (cn))) + (((bn) * (cp)))))))))))

Complete tactic proof in conservative notation

All 11 original proof lines are preserved. Only local proposition formulas are abbreviated; every abbreviation has an exact binder-safe expansion check. The linked exact edition contains the unchanged replay script.

Read the argument

Proof checkpoints

11 script commands · 3 reading checkpoints · 0 local claims

This is a reading aid, not a new proof or a proof-tree certificate. Checkpoint groups are consecutive commands, not inferred branch boundaries. Every step links to the preserved script.

Definition notation is shown below. Open the paired exact edition for the original native formulas. Source pairing is not a new equivalence certificate.

01Fix variables and assumptionsL1–8

Work with arbitrary variables or the premises of the current implication.

  1. L1
    intro ap
  2. L2
    intro an
  3. L3
    intro bp
  4. L4
    intro bn
  5. L5
    intro cp
  6. L6
    intro cn
  7. L7
    intro dp
  8. L8
    intro dn
02Separate the logical casesL9–9

Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.

  1. L9
    split
03Calculate and transport equalitiesL10–11

Carry out the recorded arithmetic or equality steps; inspect the exact commands for their direction and premises.

  1. L10
    simp [mul_comm, add_comm]
  2. L11
    simp [mul_comm, add_comm]

Library-wide reading audit

Original defined command ledger · 11 lines
  1. 0001intro ap
  2. 0002intro an
  3. 0003intro bp
  4. 0004intro bn
  5. 0005intro cp
  6. 0006intro cn
  7. 0007intro dp
  8. 0008intro dn
  9. 0009split
  10. 0010simp [mul_comm, add_comm]
  11. 0011simp [mul_comm, add_comm]