1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
|
import { Add, Multiply, Succ, _0 } from './nat';
import { Op, Rewrite, ChainRewrites, Flip, Equation, Refl } from './util';
export namespace addition {
export type Identity<A extends Op> = Rewrite<Add<A, _0>, A>;
export type IdentityR<A extends Op> = Rewrite<Add<_0, A>, A>;
export type SumSucc1<A extends Op, B extends Op> = Rewrite<Add<Succ<A>, B>, Succ<Add<A, B>>>
export type SumSucc2<A extends Op, B extends Op> = Rewrite<Add<A, Succ<B>>, Succ<Add<A, B>>>
/// Sum commutativity
export type Commutativity<A extends Op, B extends Op> = Rewrite<Add<A, B>, Add<B, A>>;
export interface Comm_Base<B extends Op> {
type: 'rewrite',
left: Equation<Add<_0, B>, Add<B, _0>>; // 0 + b = b + 0
right: ChainRewrites<[
IdentityR<B>, // b = b + 0
Flip<Identity<B>>, // b + 0 = b + 0
Refl<Add<B, _0>>, // true
], this['left']>;
};
export interface Comm_Inductive<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<[
SumSucc1<A, B>, // succ(a + b) = b + succ(a)
Commutativity<A, B>, // succ(b + a) = b + succ(a)
SumSucc2<B, A>, // succ(b + a) = succ(b + a)
Refl<Succ<Add<B, A>>>, // true
], this['left']>;
};
// Sum 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<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<Add<B, C>>, // true
], this['left']>;
};
export interface Assoc_Inductive<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<[
SumSucc1<A, B>, // succ(a + b) + c = succ(a) + (b + c)
SumSucc1<A, Add<B, C>>, // succ(a + b) + c = succ(a + (b + c))
SumSucc1<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<Succ<Add<A, Add<B, C>>>>, // true
], this['left']>;
};
}
|
