115 lines
3.1 KiB
Text
115 lines
3.1 KiB
Text
import logic
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namespace experiment
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definition Type1 := Type.{1}
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context
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variable {A : Type}
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variable f : A → A → A
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variable one : A
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variable inv : A → A
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infixl `*` := f
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postfix `^-1`:100 := inv
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definition is_assoc := ∀ a b c, (a*b)*c = a*b*c
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definition is_id := ∀ a, a*one = a
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definition is_inv := ∀ a, a*a^-1 = one
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end
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namespace algebra
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inductive mul_struct [class] (A : Type) : Type :=
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mk : (A → A → A) → mul_struct A
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inductive add_struct [class] (A : Type) : Type :=
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mk : (A → A → A) → add_struct A
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definition mul {A : Type} [s : mul_struct A] (a b : A)
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:= mul_struct.rec (fun f, f) s a b
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infixl `*` := mul
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definition add {A : Type} [s : add_struct A] (a b : A)
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:= add_struct.rec (fun f, f) s a b
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infixl `+` := add
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end algebra
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open algebra
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inductive nat : Type :=
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zero : nat,
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succ : nat → nat
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namespace nat
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constant add : nat → nat → nat
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constant mul : nat → nat → nat
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definition is_mul_struct [instance] : algebra.mul_struct nat
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:= algebra.mul_struct.mk mul
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definition is_add_struct [instance] : algebra.add_struct nat
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:= algebra.add_struct.mk add
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definition to_nat (n : num) : nat
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:= #experiment.algebra
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num.rec nat.zero (λ n, pos_num.rec (succ zero) (λ n r, r + r) (λ n r, r + r + succ zero) n) n
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end nat
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namespace algebra
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namespace semigroup
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inductive semigroup_struct [class] (A : Type) : Type :=
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mk : Π (mul : A → A → A), is_assoc mul → semigroup_struct A
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definition mul {A : Type} (s : semigroup_struct A) (a b : A)
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:= semigroup_struct.rec (fun f h, f) s a b
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definition assoc {A : Type} (s : semigroup_struct A) : is_assoc (mul s)
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:= semigroup_struct.rec (fun f h, h) s
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definition is_mul_struct [instance] (A : Type) (s : semigroup_struct A) : mul_struct A
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:= mul_struct.mk (mul s)
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inductive semigroup : Type :=
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mk : Π (A : Type), semigroup_struct A → semigroup
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definition carrier [coercion] (g : semigroup)
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:= semigroup.rec (fun c s, c) g
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definition is_semigroup [instance] (g : semigroup) : semigroup_struct (carrier g)
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:= semigroup.rec (fun c s, s) g
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end semigroup
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namespace monoid
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check semigroup.mul
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inductive monoid_struct [class] (A : Type) : Type :=
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mk_monoid_struct : Π (mul : A → A → A) (id : A), is_assoc mul → is_id mul id → monoid_struct A
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definition mul {A : Type} (s : monoid_struct A) (a b : A)
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:= monoid_struct.rec (fun mul id a i, mul) s a b
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definition assoc {A : Type} (s : monoid_struct A) : is_assoc (mul s)
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:= monoid_struct.rec (fun mul id a i, a) s
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open semigroup
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definition is_semigroup_struct [instance] (A : Type) (s : monoid_struct A) : semigroup_struct A
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:= semigroup_struct.mk (mul s) (assoc s)
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inductive monoid : Type :=
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mk_monoid : Π (A : Type), monoid_struct A → monoid
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definition carrier [coercion] (m : monoid)
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:= monoid.rec (fun c s, c) m
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definition is_monoid [instance] (m : monoid) : monoid_struct (carrier m)
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:= monoid.rec (fun c s, s) m
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end monoid
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end algebra
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section
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open algebra algebra.semigroup algebra.monoid
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variable M : monoid
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variables a b c : M
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check a*b*c*a*b*c*a*b*a*b*c*a
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check a*b
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end
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end experiment
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