From 6dd1a626f30558c7cecaf8870a9a52bd12350d8e Mon Sep 17 00:00:00 2001
From: Akshay Nair <phenax5@gmail.com>
Date: Fri, 22 Dec 2023 20:24:43 +0530
Subject: refactor: minor refactor of proofs

---
 src/equation.ts        |  59 ++++++-------
 src/natural-numbers.ts | 235 ++++++++++++++++++++++++-------------------------
 2 files changed, 145 insertions(+), 149 deletions(-)

diff --git a/src/equation.ts b/src/equation.ts
index cc668b1..e2cc2bc 100644
--- a/src/equation.ts
+++ b/src/equation.ts
@@ -1,48 +1,45 @@
-import { Op, Rewrite, ChainRewrites, Sym, Equation, VerifyEquation, assert, ApplyRewrite, Evaluate, OpToStr, SubstEq } from './utils/theorem';
+import { Op, Rewrite, ChainRewrites, Sym, Equation, VerifyEquation, assert, SubstEq } from './utils/theorem';
 
 export namespace equation {
   type F<X extends Op> = { op: 'F', a: X };
 
   export type Reflexivity<A extends Op> = Rewrite<Equation<A, A>, 'true'>;
 
-  export type Symmetry<A extends Op, B extends Op> = Rewrite<Equation<A, B>, Equation<B, A>>;
+  export type Commutativity<A extends Op, B extends Op> = Rewrite<Equation<A, B>, Equation<B, A>>;
 
   export type Congruence<A extends Op, B extends Op> = Rewrite<Equation<A, B>, Equation<F<A>, F<B>>>;
 
-  export interface SubstituteEq_Proof<A extends Op, B extends Op> {
-    type: 'rewrite',
-    known: {
-      'a = b': Equation<A, B>,
-    },
-    left: Equation<F<A>, F<B>>; // f(a) = f(b)
-    right: ChainRewrites<[
-      Sym<Congruence<A, B>>,                   // a = b
-      SubstEq<this['known']['a = b']>,         // b = b
-      Reflexivity<B>,
-    ], this['left']>;
-  };
-  export namespace spec {
+  export namespace proof {
+    export interface SubstituteEq_Proof<A extends Op, B extends Op> {
+      type: 'rewrite',
+      known: {
+        'a = b': Equation<A, B>,
+      },
+      left: Equation<F<A>, F<B>>; // f(a) = f(b)
+      right: ChainRewrites<[
+        Sym<Congruence<A, B>>,                   // a = b
+        SubstEq<this['known']['a = b']>,         // b = b
+        Reflexivity<B>,
+      ], this['left']>;
+    };
     export type substitution = [
       assert<VerifyEquation<SubstituteEq_Proof<'A', 'B'>>>,
     ]
   }
 
-  export interface Transitivity_Proof<A extends Op, B extends Op, C extends Op> {
-    type: 'rewrite',
-    known: {
-      'a = b': Equation<A, B>,
-      'b = c': Equation<B, C>,
-    },
-    left: Equation<Equation<A, B>, Equation<B, C>>; // (a = b) = (b = c)
-    right: ChainRewrites<[
-      SubstEq<this['known']['a = b']>,                                 // (b = b) = (b = c)
-      SubstEq<ApplyRewrite<this['known']['b = c'], Symmetry<B, C>>>,   // (b = b) = (c = b)
-      Reflexivity<B>,                                                       // true = (b = b)
-      Reflexivity<B>,                                                       // true = true
-      Reflexivity<'true'>,
-    ], this['left']>;
-  };
-  export namespace spec {
+  export namespace proof {
+    export interface Transitivity_Proof<A extends Op, B extends Op, C extends Op> {
+      type: 'rewrite',
+      known: {
+        'a = b': Equation<A, B>,
+        'b = c': Equation<B, C>,
+      },
+      left: Equation<A, C>; // a = c
+      right: ChainRewrites<[
+        SubstEq<this['known']['a = b']>,                   // b = c
+        Rewrite<this['known']['b = c'], 'true'>,           // true
+      ], this['left']>;
+    };
     export type transitivity = [
       assert<VerifyEquation<Transitivity_Proof<'A', 'B', 'C'>>>,
     ]
diff --git a/src/natural-numbers.ts b/src/natural-numbers.ts
index fa8a3ce..046ec4c 100644
--- a/src/natural-numbers.ts
+++ b/src/natural-numbers.ts
@@ -11,26 +11,26 @@ export namespace addition {
 
   // Commutativity
   export type Commutativity<A extends Op, B extends Op> = Rewrite<Add<A, B>, Add<B, A>>;
-  export interface Comm_Base_Proof<B extends Op> {
-    type: 'rewrite',
-    left: Equation<Add<_0, B>, Add<B, _0>>; // 0 + b = b + 0
-    right: ChainRewrites<[
-      IdentityR<B>,           // b = b + 0
-      Sym<Identity<B>>,       // b + 0 = b + 0
-      Refl,
-    ], this['left']>;
-  };
-  export interface Comm_Inductive_Proof<A extends Op, B extends Op> {
-    type: 'rewrite',
-    left: Equation<Add<Succ<A>, B>, Add<B, Succ<A>>>;  // succ(a) + b = b + succ(a)
-    right: ChainRewrites<[
-      SuccLemma<A, B>,          // succ(a + b) = b + succ(a)
-      Commutativity<A, B>,      // succ(b + a) = b + succ(a)
-      SuccLemmaR<B, A>,         // succ(b + a) = succ(b + a)
-      Refl,
-    ], this['left']>;
-  };
-  export namespace spec {
+  export namespace proof {
+    export interface Comm_Base_Proof<B extends Op> {
+      type: 'rewrite',
+      left: Equation<Add<_0, B>, Add<B, _0>>; // 0 + b = b + 0
+      right: ChainRewrites<[
+        IdentityR<B>,           // b = b + 0
+        Sym<Identity<B>>,       // b + 0 = b + 0
+        Refl,
+      ], this['left']>;
+    };
+    export interface Comm_Inductive_Proof<A extends Op, B extends Op> {
+      type: 'rewrite',
+      left: Equation<Add<Succ<A>, B>, Add<B, Succ<A>>>;  // succ(a) + b = b + succ(a)
+      right: ChainRewrites<[
+        SuccLemma<A, B>,          // succ(a + b) = b + succ(a)
+        Commutativity<A, B>,      // succ(b + a) = b + succ(a)
+        SuccLemmaR<B, A>,         // succ(b + a) = succ(b + a)
+        Refl,
+      ], this['left']>;
+    };
     export type commutativity = [
       assert<VerifyEquation<Comm_Base_Proof<'B'>>>,
       assert<VerifyEquation<Comm_Inductive_Proof<'A', 'B'>>>,
@@ -39,29 +39,28 @@ export namespace addition {
 
   // Associativity
   export type Associativity<A extends Op, B extends Op, C extends Op> = Rewrite<Add<Add<A, B>, C>, Add<A, Add<B, C>>>;
-  export interface Assoc_Base_Proof<B extends Op, C extends Op> {
-    type: 'rewrite',
-    left: Equation<Add<Add<_0, B>, C>, Add<_0, Add<B, C>>>; // (0 + b) + c = 0 + (b + c)
-    right: ChainRewrites<[
-      Commutativity<_0, B>,      // (b + 0) + c = 0 + (b + c)
-      Identity<B>,               // b + c = 0 + (b + c)
-      IdentityR<Add<B, C>>,      // b + c = b + c
-      Refl,
-    ], this['left']>;
-  };
-  export interface Assoc_Inductive_Proof<A extends Op, B extends Op, C extends Op> {
-    type: 'rewrite',
-    left: Equation<Add<Add<Succ<A>, B>, C>, Add<Succ<A>, Add<B, C>>>; // (succ(a) + b) + c = succ(a) + (b + c)
-    right: ChainRewrites<[
-      SuccLemma<A, B>,               // succ(a + b) + c = succ(a) + (b + c)
-      SuccLemma<A, Add<B, C>>,       // succ(a + b) + c = succ(a + (b + c))
-      SuccLemma<Add<A, B>, C>,       // succ((a + b) + c) = succ(a + (b + c))
-      Associativity<A, B, C>,        // succ(a + (b + c)) = succ(a + (b + c))
-      Refl,
-    ], this['left']>;
-  };
-
-  export namespace spec {
+  export namespace proof {
+    export interface Assoc_Base_Proof<B extends Op, C extends Op> {
+      type: 'rewrite',
+      left: Equation<Add<Add<_0, B>, C>, Add<_0, Add<B, C>>>; // (0 + b) + c = 0 + (b + c)
+      right: ChainRewrites<[
+        Commutativity<_0, B>,      // (b + 0) + c = 0 + (b + c)
+        Identity<B>,               // b + c = 0 + (b + c)
+        IdentityR<Add<B, C>>,      // b + c = b + c
+        Refl,
+      ], this['left']>;
+    };
+    export interface Assoc_Inductive_Proof<A extends Op, B extends Op, C extends Op> {
+      type: 'rewrite',
+      left: Equation<Add<Add<Succ<A>, B>, C>, Add<Succ<A>, Add<B, C>>>; // (succ(a) + b) + c = succ(a) + (b + c)
+      right: ChainRewrites<[
+        SuccLemma<A, B>,               // succ(a + b) + c = succ(a) + (b + c)
+        SuccLemma<A, Add<B, C>>,       // succ(a + b) + c = succ(a + (b + c))
+        SuccLemma<Add<A, B>, C>,       // succ((a + b) + c) = succ(a + (b + c))
+        Associativity<A, B, C>,        // succ(a + (b + c)) = succ(a + (b + c))
+        Refl,
+      ], this['left']>;
+    };
     export type associativity = [
       assert<VerifyEquation<Assoc_Base_Proof<'A', 'B'>>>,
       assert<VerifyEquation<Assoc_Inductive_Proof<'A', 'B', 'C'>>>,
@@ -69,16 +68,16 @@ export namespace addition {
   }
 
   // Rearrange
-  export interface Rearrange_Proof<A extends Op, B extends Op, C extends Op, D extends Op> {
-    type: 'rewrite',
-    left: Equation<Add<Add<A, B>, Add<C, D>>, Add<A, Add<Add<B, C>, D>>>; // (a + b) + (c + d) = a + ((b + c) + d)
-    right: ChainRewrites<[
-      Associativity<A, B, Add<C, D>>,   // a + (b + (c + d)) = a + ((b + c) + d)
-      Associativity<B, C, D>,           // a + (b + (c + d)) = a + (b + (c + d))
-      Refl,
-    ], this['left']>;
-  };
-  export namespace spec {
+  export namespace proof {
+    export interface Rearrange_Proof<A extends Op, B extends Op, C extends Op, D extends Op> {
+      type: 'rewrite',
+      left: Equation<Add<Add<A, B>, Add<C, D>>, Add<A, Add<Add<B, C>, D>>>; // (a + b) + (c + d) = a + ((b + c) + d)
+      right: ChainRewrites<[
+        Associativity<A, B, Add<C, D>>,   // a + (b + (c + d)) = a + ((b + c) + d)
+        Associativity<B, C, D>,           // a + (b + (c + d)) = a + (b + (c + d))
+        Refl,
+      ], this['left']>;
+    };
     export type rearrange = [
       assert<VerifyEquation<Rearrange_Proof<'A', 'B', 'C', 'D'>>>,
     ]
@@ -95,26 +94,26 @@ export namespace multiplication {
 
   // Commutativity
   export type Commutativity<A extends Op, B extends Op> = Rewrite<Multiply<A, B>, Multiply<B, A>>;
-  export interface Comm_Base_Proof<B extends Op> {
-    type: 'rewrite',
-    left: Equation<Multiply<_1, B>, Multiply<B, _1>>; // 1 * b = b * 1
-    right: ChainRewrites<[
-      IdentityR<B>,        // b = b * 1
-      Identity<B>,         // b = b
-      Refl,
-    ], this['left']>;
-  };
-  export interface Comm_Inductive_Proof<A extends Op, B extends Op> {
-    type: 'rewrite',
-    left: Equation<Multiply<Succ<A>, B>, Multiply<B, Succ<A>>>; // succ(a)*b = b*succ(a)
-    right: ChainRewrites<[
-      SuccLemma<A, B>,             // b + a*b = b*succ(a)
-      SuccLemmaR<B, A>,            // b + a*b = b + b*a
-      Commutativity<B, A>,         // b + a*b = b + a*b
-      Refl,
-    ], this['left']>;
-  };
-  export namespace spec {
+  export namespace proof {
+    export interface Comm_Base_Proof<B extends Op> {
+      type: 'rewrite',
+      left: Equation<Multiply<_1, B>, Multiply<B, _1>>; // 1 * b = b * 1
+      right: ChainRewrites<[
+        IdentityR<B>,        // b = b * 1
+        Identity<B>,         // b = b
+        Refl,
+      ], this['left']>;
+    };
+    export interface Comm_Inductive_Proof<A extends Op, B extends Op> {
+      type: 'rewrite',
+      left: Equation<Multiply<Succ<A>, B>, Multiply<B, Succ<A>>>; // succ(a)*b = b*succ(a)
+      right: ChainRewrites<[
+        SuccLemma<A, B>,             // b + a*b = b*succ(a)
+        SuccLemmaR<B, A>,            // b + a*b = b + b*a
+        Commutativity<B, A>,         // b + a*b = b + a*b
+        Refl,
+      ], this['left']>;
+    };
     export type commutativity = [
       assert<VerifyEquation<Comm_Base_Proof<'B'>>>,
       assert<VerifyEquation<Comm_Inductive_Proof<'A', 'B'>>>,
@@ -124,30 +123,30 @@ export namespace multiplication {
   // Distributivity
   export type Distributivity<A extends Op, B extends Op, C extends Op> =
     Rewrite<Multiply<Add<A, B>, C>, Add<Multiply<A, C>, Multiply<B, C>>>;
-  export interface Dist_Base_Proof<B extends Op, C extends Op> {
-    type: 'rewrite',
-    left: Equation<Multiply<Add<_1, B>, C>, Add<Multiply<_1, C>, Multiply<B, C>>>; // (1 + b)*c = 1*c + b*c
-    right: ChainRewrites<[
-      IdentityR<C>,                    // (1 + b)*c = c + b*c
-      addition.SuccLemma<_0, B>,       // succ(0 + b)*c = c + b*c
-      addition.IdentityR<B>,           // succ(b)*c = c + b*c
-      SuccLemma<B, C>,                 // c + b*c = c + b*c
-      Refl,
-    ], this['left']>;
-  };
-  export interface Dist_Inductive_Proof<A extends Op, B extends Op, C extends Op> {
-    type: 'rewrite',
-    left: Equation<Multiply<Add<Succ<A>, B>, C>, Add<Multiply<Succ<A>, C>, Multiply<B, C>>>; // (succ(a) + b)*c = succ(a)*c + b*c
-    right: ChainRewrites<[
-      addition.SuccLemma<A, B>,                                     // succ(a + b)*c = succ(a)*c + b*c
-      SuccLemma<Add<A, B>, C>,                                      // c + (a + b)*c = succ(a)*c + b*c
-      SuccLemma<A, C>,                                              // c + (a + b)*c = (c + a*c) + b*c
-      Distributivity<A, B, C>,                                      // c + (a*c + b*c) = (c + a*c) + b*c
-      addition.Associativity<C, Multiply<A, C>, Multiply<B, C>>,    // (c + a*c) + b*c = (c + a*c) + b*c
-      Refl,
-    ], this['left']>;
-  };
-  export namespace spec {
+  export namespace proof {
+    export interface Dist_Base_Proof<B extends Op, C extends Op> {
+      type: 'rewrite',
+      left: Equation<Multiply<Add<_1, B>, C>, Add<Multiply<_1, C>, Multiply<B, C>>>; // (1 + b)*c = 1*c + b*c
+      right: ChainRewrites<[
+        IdentityR<C>,                    // (1 + b)*c = c + b*c
+        addition.SuccLemma<_0, B>,       // succ(0 + b)*c = c + b*c
+        addition.IdentityR<B>,           // succ(b)*c = c + b*c
+        SuccLemma<B, C>,                 // c + b*c = c + b*c
+        Refl,
+      ], this['left']>;
+    };
+    export interface Dist_Inductive_Proof<A extends Op, B extends Op, C extends Op> {
+      type: 'rewrite',
+      left: Equation<Multiply<Add<Succ<A>, B>, C>, Add<Multiply<Succ<A>, C>, Multiply<B, C>>>; // (succ(a) + b)*c = succ(a)*c + b*c
+      right: ChainRewrites<[
+        addition.SuccLemma<A, B>,                                     // succ(a + b)*c = succ(a)*c + b*c
+        SuccLemma<Add<A, B>, C>,                                      // c + (a + b)*c = succ(a)*c + b*c
+        SuccLemma<A, C>,                                              // c + (a + b)*c = (c + a*c) + b*c
+        Distributivity<A, B, C>,                                      // c + (a*c + b*c) = (c + a*c) + b*c
+        addition.Associativity<C, Multiply<A, C>, Multiply<B, C>>,    // (c + a*c) + b*c = (c + a*c) + b*c
+        Refl,
+      ], this['left']>;
+    };
     export type distributivity = [
       assert<VerifyEquation<Dist_Base_Proof<'B', 'C'>>>,
       assert<VerifyEquation<Dist_Inductive_Proof<'A', 'B', 'C'>>>,
@@ -157,27 +156,27 @@ export namespace multiplication {
   // Associativity
   export type Associativity<A extends Op, B extends Op, C extends Op> =
     Rewrite<Multiply<Multiply<A, B>, C>, Multiply<A, Multiply<B, C>>>;
-  export interface Assoc_Base_Proof<B extends Op, C extends Op> {
-    type: 'rewrite',
-    left: Equation<Multiply<Multiply<_1, B>, C>, Multiply<_1, Multiply<B, C>>>; // (1*b)*c = 1*(b*c)
-    right: ChainRewrites<[
-      IdentityR<B>,                     // b*c = 1*(b*c)
-      IdentityR<Multiply<B, C>>,        // b*c = b*c
-      Refl,
-    ], this['left']>;
-  };
-  export interface Assoc_Inductive_Proof<A extends Op, B extends Op, C extends Op> {
-    type: 'rewrite',
-    left: Equation<Multiply<Multiply<Succ<A>, B>, C>, Multiply<Succ<A>, Multiply<B, C>>>; // (succ(a)*b)*c = succ(a)*(b*c)
-    right: ChainRewrites<[
-      SuccLemma<A, B>,                         // (b + a*b)*c = succ(a) * (b*c)
-      Distributivity<B, Multiply<A, B>, C>,    // b*c + (a*b)*c = succ(a) * (b*c)
-      SuccLemma<A, Multiply<B, C>>,            // b*c + (a*b)*c = b*c + a*(b*c)
-      Associativity<A, B, C>,                  // b*c + a*(b*c) = b*c + a*(b*c)
-      Refl,
-    ], this['left']>;
-  };
-  export namespace spec {
+  export namespace proof {
+    export interface Assoc_Base_Proof<B extends Op, C extends Op> {
+      type: 'rewrite',
+      left: Equation<Multiply<Multiply<_1, B>, C>, Multiply<_1, Multiply<B, C>>>; // (1*b)*c = 1*(b*c)
+      right: ChainRewrites<[
+        IdentityR<B>,                     // b*c = 1*(b*c)
+        IdentityR<Multiply<B, C>>,        // b*c = b*c
+        Refl,
+      ], this['left']>;
+    };
+    export interface Assoc_Inductive_Proof<A extends Op, B extends Op, C extends Op> {
+      type: 'rewrite',
+      left: Equation<Multiply<Multiply<Succ<A>, B>, C>, Multiply<Succ<A>, Multiply<B, C>>>; // (succ(a)*b)*c = succ(a)*(b*c)
+      right: ChainRewrites<[
+        SuccLemma<A, B>,                         // (b + a*b)*c = succ(a) * (b*c)
+        Distributivity<B, Multiply<A, B>, C>,    // b*c + (a*b)*c = succ(a) * (b*c)
+        SuccLemma<A, Multiply<B, C>>,            // b*c + (a*b)*c = b*c + a*(b*c)
+        Associativity<A, B, C>,                  // b*c + a*(b*c) = b*c + a*(b*c)
+        Refl,
+      ], this['left']>;
+    };
     export type associativity = [
       assert<VerifyEquation<Assoc_Base_Proof<'B', 'C'>>>,
       assert<VerifyEquation<Assoc_Inductive_Proof<'A', 'B', 'C'>>>,
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