michael/lean2
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

refactor(library/algebra/order): change strong order pair, adopt new naming conventions

Browse source
This commit is contained in:
Jeremy Avigad 2014-11-28 18:13:01 -05:00 committed by Leonardo de Moura
parent 1b13562591
commit 1bffd8dd21
2 changed files with 85 additions and 75 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

131
library/algebra/order.lean
View file

@ -45,22 +45,22 @@ notation a >= b := has_le.ge a b
definition has_lt.gt {A : Type} [s : has_lt A] (a b : A) := b < a definition has_lt.gt {A : Type} [s : has_lt A] (a b : A) := b < a
notation a > b := has_lt.gt a b notation a > b := has_lt.gt a b
theorem eq_le_trans {A : Type} [s : has_le A] {a b c : A} (H1 : a = b) (H2 : b ≤ c) : theorem le_of_eq_of_le {A : Type} [s : has_le A] {a b c : A} (H1 : a = b) (H2 : b ≤ c) :
a ≤ c := H1⁻¹ ▸ H2 a ≤ c := H1⁻¹ ▸ H2
theorem le_eq_trans {A : Type} [s : has_le A] {a b c : A} (H1 : a ≤ b) (H2 : b = c) : theorem le_of_le_of_eq {A : Type} [s : has_le A] {a b c : A} (H1 : a ≤ b) (H2 : b = c) :
a ≤ c := H2 ▸ H1 a ≤ c := H2 ▸ H1
theorem eq_lt_trans {A : Type} [s : has_lt A] {a b c : A} (H1 : a = b) (H2 : b < c) : theorem lt_of_eq_of_lt {A : Type} [s : has_lt A] {a b c : A} (H1 : a = b) (H2 : b < c) :
a < c := H1⁻¹ ▸ H2 a < c := H1⁻¹ ▸ H2
theorem lt_eq_trans {A : Type} [s : has_lt A] {a b c : A} (H1 : a < b) (H2 : b = c) : theorem lt_of_lt_of_eq {A : Type} [s : has_lt A] {a b c : A} (H1 : a < b) (H2 : b = c) :
a < c := H2 ▸ H1 a < c := H2 ▸ H1
calc_trans eq_le_trans calc_trans le_of_eq_of_le
calc_trans le_eq_trans calc_trans le_of_le_of_eq
calc_trans eq_lt_trans calc_trans lt_of_eq_of_lt
calc_trans lt_eq_trans calc_trans lt_of_lt_of_eq
/- weak orders -/ /- weak orders -/
@ -70,18 +70,18 @@ structure weak_order [class] (A : Type) extends has_le A :=
(le_trans : ∀a b c, le a b → le b c → le a c) (le_trans : ∀a b c, le a b → le b c → le a c)
(le_antisym : ∀a b, le a b → le b a → a = b) (le_antisym : ∀a b, le a b → le b a → a = b)
theorem le_refl [s : weak_order A] (a : A) : a ≤ a := !weak_order.le_refl theorem le.refl [s : weak_order A] (a : A) : a ≤ a := !weak_order.le_refl
theorem le_trans [s : weak_order A] {a b c : A} : a ≤ b → b ≤ c → a ≤ c := !weak_order.le_trans theorem le.trans [s : weak_order A] {a b c : A} : a ≤ b → b ≤ c → a ≤ c := !weak_order.le_trans
calc_trans le_trans calc_trans le.trans
theorem le_antisym [s : weak_order A] {a b : A} : a ≤ b → b ≤ a → a = b := !weak_order.le_antisym theorem le.antisym [s : weak_order A] {a b : A} : a ≤ b → b ≤ a → a = b := !weak_order.le_antisym
structure linear_weak_order [class] (A : Type) extends weak_order A := structure linear_weak_order [class] (A : Type) extends weak_order A :=
(le_total : ∀a b, le a b ∨ le b a) (le_total : ∀a b, le a b ∨ le b a)
theorem le_total [s : linear_weak_order A] {a b : A} : a ≤ b ∨ b ≤ a := theorem le.total [s : linear_weak_order A] {a b : A} : a ≤ b ∨ b ≤ a :=
!linear_weak_order.le_total !linear_weak_order.le_total
@ -91,28 +91,30 @@ structure strict_order [class] (A : Type) extends has_lt A :=
(lt_irrefl : ∀a, ¬ lt a a) (lt_irrefl : ∀a, ¬ lt a a)
(lt_trans : ∀a b c, lt a b → lt b c → lt a c) (lt_trans : ∀a b c, lt a b → lt b c → lt a c)
theorem lt_irrefl [s : strict_order A] (a : A) : ¬ a < a := !strict_order.lt_irrefl theorem lt.irrefl [s : strict_order A] (a : A) : ¬ a < a := !strict_order.lt_irrefl
theorem lt_trans [s : strict_order A] {a b c : A} : a < b → b < c → a < c := !strict_order.lt_trans theorem lt.trans [s : strict_order A] {a b c : A} : a < b → b < c → a < c := !strict_order.lt_trans
calc_trans lt_trans calc_trans lt.trans
theorem lt_imp_ne [s : strict_order A] {a b : A} : a < b → a ≠ b := theorem lt.ne [s : strict_order A] {a b : A} : a < b → a ≠ b :=
assume lt_ab : a < b, assume eq_ab : a = b, lt_irrefl a (eq_ab⁻¹ ▸ lt_ab) assume lt_ab : a < b, assume eq_ab : a = b, lt.irrefl a (eq_ab⁻¹ ▸ lt_ab)
/- well-founded orders -/ /- well-founded orders -/
-- TODO: do these duplicate what Leo has done? if so, eliminate
structure wf_strict_order [class] (A : Type) extends strict_order A := structure wf_strict_order [class] (A : Type) extends strict_order A :=
(wf_rec : ∀P : A → Type, (∀x, (∀y, lt y x → P y) → P x) → ∀x, P x) (wf_rec : ∀P : A → Type, (∀x, (∀y, lt y x → P y) → P x) → ∀x, P x)
definition wf_rec_on {A : Type} [s : wf_strict_order A] {P : A → Type} definition wf.rec_on {A : Type} [s : wf_strict_order A] {P : A → Type}
(x : A) (H : ∀x, (∀y, wf_strict_order.lt y x → P y) → P x) : P x := (x : A) (H : ∀x, (∀y, wf_strict_order.lt y x → P y) → P x) : P x :=
wf_strict_order.wf_rec P H x wf_strict_order.wf_rec P H x
theorem wf_ind_on.{u v} {A : Type.{u}} [s : wf_strict_order.{u 0} A] {P : A → Prop} theorem wf.ind_on.{u v} {A : Type.{u}} [s : wf_strict_order.{u 0} A] {P : A → Prop}
(x : A) (H : ∀x, (∀y, wf_strict_order.lt y x → P y) → P x) : P x := (x : A) (H : ∀x, (∀y, wf_strict_order.lt y x → P y) → P x) : P x :=
wf_rec_on x H wf.rec_on x H
/- structures with a weak and a strict order -/ /- structures with a weak and a strict order -/
@ -120,14 +122,14 @@ wf_rec_on x H
structure order_pair [class] (A : Type) extends weak_order A, has_lt A := structure order_pair [class] (A : Type) extends weak_order A, has_lt A :=
(lt_iff_le_ne : ∀a b, lt a b ↔ (le a b ∧ a ≠ b)) (lt_iff_le_ne : ∀a b, lt a b ↔ (le a b ∧ a ≠ b))
theorem lt_iff_le_ne [s : order_pair A] {a b : A} : a < b ↔ (a ≤ b ∧ a ≠ b) := theorem lt_iff_le_and_ne [s : order_pair A] {a b : A} : a < b ↔ (a ≤ b ∧ a ≠ b) :=
!order_pair.lt_iff_le_ne !order_pair.lt_iff_le_ne
theorem lt_imp_le [s : order_pair A] {a b : A} (H : a < b) : a ≤ b := theorem le_of_lt [s : order_pair A] {a b : A} (H : a < b) : a ≤ b :=
and.elim_left (iff.mp lt_iff_le_ne H) and.elim_left (iff.mp lt_iff_le_and_ne H)
theorem le_ne_imp_lt [s : order_pair A] {a b : A} (H1 : a ≤ b) (H2 : a ≠ b) : a < b := theorem lt_of_le_of_ne [s : order_pair A] {a b : A} (H1 : a ≤ b) (H2 : a ≠ b) : a < b :=
iff.mp (iff.symm lt_iff_le_ne) (and.intro H1 H2) iff.mp (iff.symm lt_iff_le_and_ne) (and.intro H1 H2)
definition order_pair.to_strict_order [instance] [s : order_pair A] : strict_order A := definition order_pair.to_strict_order [instance] [s : order_pair A] : strict_order A :=
strict_order.mk strict_order.mk
@ -135,49 +137,49 @@ strict_order.mk
(show ∀a, ¬ a < a, from (show ∀a, ¬ a < a, from
take a, take a,
assume H : a < a, assume H : a < a,
have H1 : a ≠ a, from and.elim_right (iff.mp !lt_iff_le_ne H), have H1 : a ≠ a, from and.elim_right (iff.mp !lt_iff_le_and_ne H),
H1 rfl) H1 rfl)
(show ∀a b c, a < b → b < c → a < c, from (show ∀a b c, a < b → b < c → a < c, from
take a b c, take a b c,
assume lt_ab : a < b, assume lt_ab : a < b,
have le_ab : a ≤ b, from lt_imp_le lt_ab, have le_ab : a ≤ b, from le_of_lt lt_ab,
assume lt_bc : b < c, assume lt_bc : b < c,
have le_bc : b ≤ c, from lt_imp_le lt_bc, have le_bc : b ≤ c, from le_of_lt lt_bc,
have le_ac : a ≤ c, from le_trans le_ab le_bc, have le_ac : a ≤ c, from le.trans le_ab le_bc,
have ne_ac : a ≠ c, from have ne_ac : a ≠ c, from
assume eq_ac : a = c, assume eq_ac : a = c,
have le_ba : b ≤ a, from eq_ac⁻¹ ▸ le_bc, have le_ba : b ≤ a, from eq_ac⁻¹ ▸ le_bc,
have eq_ab : a = b, from le_antisym le_ab le_ba, have eq_ab : a = b, from le.antisym le_ab le_ba,
have ne_ab : a ≠ b, from and.elim_right (iff.mp lt_iff_le_ne lt_ab), have ne_ab : a ≠ b, from and.elim_right (iff.mp lt_iff_le_and_ne lt_ab),
ne_ab eq_ab, ne_ab eq_ab,
show a < c, from le_ne_imp_lt le_ac ne_ac) show a < c, from lt_of_le_of_ne le_ac ne_ac)
theorem lt_le_trans [s : order_pair A] {a b c : A} : a < b → b ≤ c → a < c := theorem lt_of_lt_of_le [s : order_pair A] {a b c : A} : a < b → b ≤ c → a < c :=
assume lt_ab : a < b, assume lt_ab : a < b,
assume le_bc : b ≤ c, assume le_bc : b ≤ c,
have le_ac : a ≤ c, from le_trans (lt_imp_le lt_ab) le_bc, have le_ac : a ≤ c, from le.trans (le_of_lt lt_ab) le_bc,
have ne_ac : a ≠ c, from have ne_ac : a ≠ c, from
assume eq_ac : a = c, assume eq_ac : a = c,
have le_ba : b ≤ a, from eq_ac⁻¹ ▸ le_bc, have le_ba : b ≤ a, from eq_ac⁻¹ ▸ le_bc,
have eq_ab : a = b, from le_antisym (lt_imp_le lt_ab) le_ba, have eq_ab : a = b, from le.antisym (le_of_lt lt_ab) le_ba,
show false, from lt_imp_ne lt_ab eq_ab, show false, from lt.ne lt_ab eq_ab,
show a < c, from le_ne_imp_lt le_ac ne_ac show a < c, from lt_of_le_of_ne le_ac ne_ac
theorem le_lt_trans [s : order_pair A] {a b c : A} : a ≤ b → b < c → a < c := theorem lt_of_le_of_lt [s : order_pair A] {a b c : A} : a ≤ b → b < c → a < c :=
assume le_ab : a ≤ b, assume le_ab : a ≤ b,
assume lt_bc : b < c, assume lt_bc : b < c,
have le_ac : a ≤ c, from le_trans le_ab (lt_imp_le lt_bc), have le_ac : a ≤ c, from le.trans le_ab (le_of_lt lt_bc),
have ne_ac : a ≠ c, from have ne_ac : a ≠ c, from
assume eq_ac : a = c, assume eq_ac : a = c,
have le_cb : c ≤ b, from eq_ac ▸ le_ab, have le_cb : c ≤ b, from eq_ac ▸ le_ab,
have eq_bc : b = c, from le_antisym (lt_imp_le lt_bc) le_cb, have eq_bc : b = c, from le.antisym (le_of_lt lt_bc) le_cb,
show false, from lt_imp_ne lt_bc eq_bc, show false, from lt.ne lt_bc eq_bc,
show a < c, from le_ne_imp_lt le_ac ne_ac show a < c, from lt_of_le_of_ne le_ac ne_ac
calc_trans le_lt_trans calc_trans lt_of_lt_of_le
calc_trans lt_le_trans calc_trans lt_of_le_of_lt
structure strong_order_pair [class] (A : Type) extends strict_order A, has_le A := structure strong_order_pair [class] (A : Type) extends order_pair A :=
(le_iff_lt_or_eq : ∀a b, le a b ↔ lt a b ∨ a = b) (le_iff_lt_or_eq : ∀a b, le a b ↔ lt a b ∨ a = b)
theorem le_iff_lt_or_eq [s : strong_order_pair A] {a b : A} : a ≤ b ↔ a < b ∨ a = b := theorem le_iff_lt_or_eq [s : strong_order_pair A] {a b : A} : a ≤ b ↔ a < b ∨ a = b :=
@ -186,19 +188,24 @@ theorem le_iff_lt_or_eq [s : strong_order_pair A] {a b : A} : a ≤ b ↔ a < b
theorem le_imp_lt_or_eq [s : strong_order_pair A] {a b : A} (le_ab : a ≤ b) : a < b ∨ a = b := theorem le_imp_lt_or_eq [s : strong_order_pair A] {a b : A} (le_ab : a ≤ b) : a < b ∨ a = b :=
iff.mp le_iff_lt_or_eq le_ab iff.mp le_iff_lt_or_eq le_ab
definition strong_order_pair.to_order_pair [instance] [s : strong_order_pair A] : order_pair A := -- We can also construct a strong order pair by defining a strict order, and then defining
order_pair.mk -- x ≤ y ↔ x < y ∨ x = y
strong_order_pair.le
(take a, show a ≤ a, from iff.mp (iff.symm le_iff_lt_or_eq) (or.intro_right _ rfl)) structure strict_order_with_le [class] (A : Type) extends strict_order A, has_le A :=
(le_iff_lt_or_eq : ∀a b, le a b ↔ lt a b ∨ a = b)
definition strict_order_with_le.to_order_pair [instance] [s : strict_order_with_le A] : strong_order_pair A :=
strong_order_pair.mk strict_order_with_le.le
(take a, show a ≤ a, from iff.mp (iff.symm !strict_order_with_le.le_iff_lt_or_eq) (or.intro_right _ rfl))
(take a b c, (take a b c,
assume le_ab : a ≤ b, assume le_ab : a ≤ b,
assume le_bc : b ≤ c, assume le_bc : b ≤ c,
show a ≤ c, from show a ≤ c, from
or.elim (le_imp_lt_or_eq le_ab) or.elim (iff.mp !strict_order_with_le.le_iff_lt_or_eq le_ab)
(assume lt_ab : a < b, (assume lt_ab : a < b,
or.elim (le_imp_lt_or_eq le_bc) or.elim (iff.mp !strict_order_with_le.le_iff_lt_or_eq le_bc)
(assume lt_bc : b < c, (assume lt_bc : b < c,
iff.elim_right le_iff_lt_or_eq (or.intro_left _ (lt_trans lt_ab lt_bc))) iff.elim_right !strict_order_with_le.le_iff_lt_or_eq (or.intro_left _ (lt.trans lt_ab lt_bc)))
(assume eq_bc : b = c, eq_bc ▸ le_ab)) (assume eq_bc : b = c, eq_bc ▸ le_ab))
(assume eq_ab : a = b, (assume eq_ab : a = b,
eq_ab⁻¹ ▸ le_bc)) eq_ab⁻¹ ▸ le_bc))
@ -206,21 +213,25 @@ order_pair.mk
assume le_ab : a ≤ b, assume le_ab : a ≤ b,
assume le_ba : b ≤ a, assume le_ba : b ≤ a,
show a = b, from show a = b, from
or.elim (le_imp_lt_or_eq le_ab) or.elim (iff.mp !strict_order_with_le.le_iff_lt_or_eq le_ab)
(assume lt_ab : a < b, (assume lt_ab : a < b,
or.elim (le_imp_lt_or_eq le_ba) or.elim (iff.mp !strict_order_with_le.le_iff_lt_or_eq le_ba)
(assume lt_ba : b < a, absurd (lt_trans lt_ab lt_ba) (lt_irrefl a)) (assume lt_ba : b < a, absurd (lt.trans lt_ab lt_ba) (lt.irrefl a))
(assume eq_ba : b = a, eq_ba⁻¹)) (assume eq_ba : b = a, eq_ba⁻¹))
(assume eq_ab : a = b, eq_ab)) (assume eq_ab : a = b, eq_ab))
strong_order_pair.lt strict_order_with_le.lt
(take a b, (take a b,
iff.intro iff.intro
(assume lt_ab : a < b, (assume lt_ab : a < b,
have le_ab : a ≤ b, from iff.elim_right le_iff_lt_or_eq (or.intro_left _ lt_ab), have le_ab : a ≤ b, from iff.elim_right !strict_order_with_le.le_iff_lt_or_eq (or.intro_left _ lt_ab),
show a ≤ b ∧ a ≠ b, from and.intro le_ab (lt_imp_ne lt_ab)) show a ≤ b ∧ a ≠ b, from and.intro le_ab (lt.ne lt_ab))
(assume H : a ≤ b ∧ a ≠ b, (assume H : a ≤ b ∧ a ≠ b,
have H1 : a < b ∨ a = b, from le_imp_lt_or_eq (and.elim_left H), have H1 : a < b ∨ a = b, from iff.mp !strict_order_with_le.le_iff_lt_or_eq (and.elim_left H),
show a < b, from or.resolve_left H1 (and.elim_right H))) show a < b, from or.resolve_left H1 (and.elim_right H)))
strict_order_with_le.le_iff_lt_or_eq
/- linear orders -/
structure linear_order_pair (A : Type) extends order_pair A, linear_weak_order A structure linear_order_pair (A : Type) extends order_pair A, linear_weak_order A

29
library/algebra/ordered_group.lean
View file

@ -36,27 +36,27 @@ section
(add_comm c a) ▸ (add_comm c b) ▸ (add_le_left H c) (add_comm c a) ▸ (add_comm c b) ▸ (add_le_left H c)
theorem add_le {a b c d : A} (Hab : a ≤ b) (Hcd : c ≤ d) : a + c ≤ b + d := theorem add_le {a b c d : A} (Hab : a ≤ b) (Hcd : c ≤ d) : a + c ≤ b + d :=
le_trans (add_le_right Hab c) (add_le_left Hcd b) le.trans (add_le_right Hab c) (add_le_left Hcd b)
theorem add_lt_left {a b : A} (H : a < b) (c : A) : c + a < c + b := theorem add_lt_left {a b : A} (H : a < b) (c : A) : c + a < c + b :=
have H1 : c + a ≤ c + b, from add_le_left (lt_imp_le H) c, have H1 : c + a ≤ c + b, from add_le_left (le_of_lt H) c,
have H2 : c + a ≠ c + b, from have H2 : c + a ≠ c + b, from
take H3 : c + a = c + b, take H3 : c + a = c + b,
have H4 : a = b, from add_left_cancel H3, have H4 : a = b, from add_left_cancel H3,
lt_imp_ne H H4, lt.ne H H4,
le_ne_imp_lt H1 H2 lt_of_le_of_ne H1 H2
theorem add_lt_right {a b : A} (H : a < b) (c : A) : a + c < b + c := theorem add_lt_right {a b : A} (H : a < b) (c : A) : a + c < b + c :=
(add_comm c a) ▸ (add_comm c b) ▸ (add_lt_left H c) (add_comm c a) ▸ (add_comm c b) ▸ (add_lt_left H c)
theorem add_lt {a b c d : A} (Hab : a < b) (Hcd : c < d) : a + c < b + d := theorem add_lt {a b c d : A} (Hab : a < b) (Hcd : c < d) : a + c < b + d :=
lt_trans (add_lt_right Hab c) (add_lt_left Hcd b) lt.trans (add_lt_right Hab c) (add_lt_left Hcd b)
theorem add_le_lt {a b c d : A} (Hab : a ≤ b) (Hcd : c < d) : a + c < b + d := theorem add_le_lt {a b c d : A} (Hab : a ≤ b) (Hcd : c < d) : a + c < b + d :=
le_lt_trans (add_le_right Hab c) (add_lt_left Hcd b) lt_of_le_of_lt (add_le_right Hab c) (add_lt_left Hcd b)
theorem add_lt_le {a b c d : A} (Hab : a < b) (Hcd : c ≤ d) : a + c < b + d := theorem add_lt_le {a b c d : A} (Hab : a < b) (Hcd : c ≤ d) : a + c < b + d :=
lt_le_trans (add_lt_right Hab c) (add_le_left Hcd b) lt_of_lt_of_le (add_lt_right Hab c) (add_le_left Hcd b)
-- here we start using add_le_left_cancel. -- here we start using add_le_left_cancel.
theorem add_le_left_cancel {a b c : A} (H : a + b ≤ a + c) : b ≤ c := theorem add_le_left_cancel {a b c : A} (H : a + b ≤ a + c) : b ≤ c :=
@ -66,10 +66,10 @@ section
add_le_left_cancel ((add_comm a b) ▸ (add_comm c b) ▸ H) add_le_left_cancel ((add_comm a b) ▸ (add_comm c b) ▸ H)
theorem add_lt_left_cancel {a b c : A} (H : a + b < a + c) : b < c := theorem add_lt_left_cancel {a b c : A} (H : a + b < a + c) : b < c :=
have H1 : b ≤ c, from add_le_left_cancel (lt_imp_le H), have H1 : b ≤ c, from add_le_left_cancel (le_of_lt H),
have H2 : b ≠ c, from have H2 : b ≠ c, from
assume H3 : b = c, lt_irrefl _ (H3 ▸ H), assume H3 : b = c, lt.irrefl _ (H3 ▸ H),
le_ne_imp_lt H1 H2 lt_of_le_of_ne H1 H2
theorem add_lt_right_cancel {a b c : A} (H : a + b < c + b) : a < c := theorem add_lt_right_cancel {a b c : A} (H : a + b < c + b) : a < c :=
add_lt_left_cancel ((add_comm a b) ▸ (add_comm c b) ▸ H) add_lt_left_cancel ((add_comm a b) ▸ (add_comm c b) ▸ H)
@ -101,7 +101,6 @@ section
theorem add_nonpos_nonpos {a b : A} (Ha : a ≤ 0) (Hb : b ≤ 0) : a + b ≤ 0 := theorem add_nonpos_nonpos {a b : A} (Ha : a ≤ 0) (Hb : b ≤ 0) : a + b ≤ 0 :=
!add_left_id ▸ (add_le Ha Hb) !add_left_id ▸ (add_le Ha Hb)
calc_trans le_eq_trans
theorem add_neg_nonpos {a b : A} (Ha : a < 0) (Hb : b ≤ 0) : a + b < 0 := theorem add_neg_nonpos {a b : A} (Ha : a < 0) (Hb : b ≤ 0) : a + b < 0 :=
!add_left_id ▸ (add_lt_le Ha Hb) !add_left_id ▸ (add_lt_le Ha Hb)
@ -121,13 +120,13 @@ section
a = a + 0 : add_right_id a = a + 0 : add_right_id
... ≤ a + b : add_le_left Hb ... ≤ a + b : add_le_left Hb
... = 0 : Hab, ... = 0 : Hab,
have Haz : a = 0, from le_antisym Ha' Ha, have Haz : a = 0, from le.antisym Ha' Ha,
have Hb' : b ≤ 0, from have Hb' : b ≤ 0, from
calc calc
b = 0 + b : add_left_id b = 0 + b : add_left_id
... ≤ a + b : add_le_right Ha ... ≤ a + b : add_le_right Ha
... = 0 : Hab, ... = 0 : Hab,
have Hbz : b = 0, from le_antisym Hb' Hb, have Hbz : b = 0, from le.antisym Hb' Hb,
and.intro Haz Hbz) and.intro Haz Hbz)
(assume Hab : a = 0 ∧ b = 0, (assume Hab : a = 0 ∧ b = 0,
(and.elim_left Hab)⁻¹ ▸ (and.elim_right Hab)⁻¹ ▸ (add_right_id 0)) (and.elim_left Hab)⁻¹ ▸ (and.elim_right Hab)⁻¹ ▸ (add_right_id 0))
@ -161,8 +160,8 @@ structure ordered_comm_group [class] (A : Type) extends add_comm_group A, order_
definition ordered_comm_group.to_ordered_cancel_comm_monoid [instance] (A : Type) definition ordered_comm_group.to_ordered_cancel_comm_monoid [instance] (A : Type)
[s : ordered_comm_group A] : ordered_cancel_comm_monoid A := [s : ordered_comm_group A] : ordered_cancel_comm_monoid A :=
ordered_cancel_comm_monoid.mk has_add.add add_assoc !has_zero.zero add_left_id add_right_id add_comm ordered_cancel_comm_monoid.mk has_add.add add_assoc !has_zero.zero add_left_id add_right_id add_comm
(@add_left_cancel _ _) (@add_right_cancel _ _) has_le.le le_refl (@le_trans _ _) (@le_antisym _ _) (@add_left_cancel _ _) (@add_right_cancel _ _) has_le.le le.refl (@le.trans _ _) (@le.antisym _ _)
has_lt.lt (@lt_iff_le_ne _ _) ordered_comm_group.add_le_left has_lt.lt (@lt_iff_le_and_ne _ _) ordered_comm_group.add_le_left
proof proof
take a b c : A, take a b c : A,
assume H : c + a ≤ c + b, assume H : c + a ≤ c + b,