SilverSight/coq/hachimoji_encode.v
allaun 3b6baec64e wip: durability snapshot of local working tree (pre-existing, uncommitted)
Snapshot of previously-uncommitted local work so nothing is lost after the
power outage. NOT reviewed for correctness — a WIP checkpoint, not a feature:
- multi-language hachimoji encoders (c/cpp/fortran/julia/octave/r/scala/go/rust/coq)
- formal Lean WIP (BraidTree, Eisenstein, HachimojiCapture, MathlibConnect,
  ModularFormBridge, ClusterManifold) + lakefile + E8Sidon edit
- docs/, experiments/ (epyc oisc benches), deploy/, scripts, test scaffolding
- .gitignore: exclude **/target/ and Coq build artifacts

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-02 20:49:53 -05:00

102 lines
2.8 KiB
Coq

From Stdlib Require Import Arith Lia.
From Stdlib Require Import List.
Import ListNotations.
(* ----- sigma3: sum of cubes of divisors ----- *)
Fixpoint divisors_aux (n d : nat) : list nat :=
match d with
| 0 => []
| S d' =>
if Nat.eqb (Nat.modulo n (S d')) 0
then (S d') :: divisors_aux n d'
else divisors_aux n d'
end.
Definition divisors (n : nat) : list nat :=
match n with
| 0 => []
| _ => divisors_aux n n
end.
Definition sigma3 (n : nat) : nat :=
fold_right (fun d acc => d * d * d + acc) 0 (divisors n).
(* ----- hachimoji_letter: sigma3 mod 8 ----- *)
Definition hachimoji_letter (s3 : nat) : nat :=
Nat.modulo s3 8.
(* ----- cartan_weight: 273 if equal, 256 if complementary, 0 otherwise ----- *)
(* Complementary hachimoji letters sum to a multiple of 8. *)
Definition cartan_weight (a b : nat) : nat :=
if Nat.eqb a b then 273
else if Nat.eqb (Nat.modulo (a + b) 8) 0 then 256
else 0.
(* ----- Helper: C(k,2) = k*(k-1)/2 via tail recursion ----- *)
Fixpoint tail_pair_count (k : nat) : nat :=
match k with
| 0 | 1 => 0
| S k' => k' + tail_pair_count k'
end.
(* ----- angrysphinx_gate ----- *)
(* Collisions = number of unordered pairs among tail elements (i.e., among *)
(* elements after the first). Energy = 273 - 239*collisions, saturating at *)
(* zero. The gate passes iff energy > 0. The constant 239 is 273 - 34, where *)
(* 34 is the single-collision residual energy. *)
Definition angrysphinx_gate (els : list nat) : bool * nat * nat :=
let n := length els in
let collisions :=
match n with
| 0 | 1 => 0
| S n' => tail_pair_count n'
end
in
let penalty := collisions * 239 in
let energy := Nat.sub 273 penalty in
let passed := negb (Nat.eqb energy 0) in
(passed, collisions, energy).
(* ----- hachimoji_encode ----- *)
Definition hachimoji_encode (n : nat) : nat * nat :=
let s3 := sigma3 n in
(s3, hachimoji_letter s3).
(* ===== COMPUTE DIRECTIVES ===== *)
(* sigma3 verification *)
Compute sigma3 1. (* = 1 *)
Compute sigma3 2. (* = 9 *)
Compute sigma3 3. (* = 28 *)
Compute sigma3 10. (* = 1134 *)
(* angrysphinx_gate verification *)
Compute angrysphinx_gate [1;2]. (* = (true, 0, 273) *)
Compute angrysphinx_gate [1;2;3]. (* = (true, 1, 34) *)
Compute angrysphinx_gate [1;2;3;4]. (* = (false, 3, 0) *)
(* Test sigma3 for all n=1..10 *)
Compute sigma3 1.
Compute sigma3 2.
Compute sigma3 3.
Compute sigma3 4.
Compute sigma3 5.
Compute sigma3 6.
Compute sigma3 7.
Compute sigma3 8.
Compute sigma3 9.
Compute sigma3 10.
(* ===== THEOREMS ===== *)
Theorem gate_12_passes : angrysphinx_gate [1;2] = (true, 0, 273).
Proof. reflexivity. Qed.
Theorem gate_1234_fails : angrysphinx_gate [1;2;3;4] = (false, 3, 0).
Proof. reflexivity. Qed.