feat(builtin/Nat): flip orientation of associativity axioms for + and *

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2014-01-20 15:38:00 -08:00
parent d1bd56b3d3
commit 97ead50a3e
9 changed files with 79 additions and 44 deletions

View file

@ -54,7 +54,7 @@ theorem OddPlusOne {a : Nat} (H : odd a) : even (a + 1)
:= obtain (w : Nat) (Hw : a = 2*w + 1), from H,
exists_intro (w + 1)
(calc a + 1 = 2*w + 1 + 1 : { Hw }
... = 2*w + (1 + 1) : symm (add_assoc _ _ _)
... = 2*w + (1 + 1) : add_assoc _ _ _
... = 2*w + 2*1 : refl _
... = 2*(w + 1) : symm (distributer _ _ _))

View file

@ -83,15 +83,15 @@ theorem add_comm (a b : Nat) : a + b = b + a
... = (n + a) + 1 : { iH }
... = (n + 1) + a : symm (add_succl n a))
theorem add_assoc (a b c : Nat) : a + (b + c) = (a + b) + c
:= induction_on a
theorem add_assoc (a b c : Nat) : (a + b) + c = a + (b + c)
:= symm (induction_on a
(calc 0 + (b + c) = b + c : add_zerol (b + c)
... = (0 + b) + c : { symm (add_zerol b) })
(λ (n : Nat) (iH : n + (b + c) = (n + b) + c),
calc (n + 1) + (b + c) = (n + (b + c)) + 1 : add_succl n (b + c)
... = ((n + b) + c) + 1 : { iH }
... = ((n + b) + 1) + c : symm (add_succl (n + b) c)
... = ((n + 1) + b) + c : { have (n + b) + 1 = (n + 1) + b : symm (add_succl n b) })
... = ((n + 1) + b) + c : { have (n + b) + 1 = (n + 1) + b : symm (add_succl n b) }))
theorem mul_zerol (a : Nat) : 0 * a = 0
:= induction_on a
@ -109,12 +109,12 @@ theorem mul_succl (a b : Nat) : (a + 1) * b = a * b + b
(λ (n : Nat) (iH : (a + 1) * n = a * n + n),
calc (a + 1) * (n + 1) = (a + 1) * n + (a + 1) : mul_succr (a + 1) n
... = a * n + n + (a + 1) : { iH }
... = a * n + n + a + 1 : add_assoc (a * n + n) a 1
... = a * n + (n + a) + 1 : { have a * n + n + a = a * n + (n + a) : symm (add_assoc (a * n) n a) }
... = a * n + n + a + 1 : symm (add_assoc (a * n + n) a 1)
... = a * n + (n + a) + 1 : { have a * n + n + a = a * n + (n + a) : add_assoc (a * n) n a }
... = a * n + (a + n) + 1 : { add_comm n a }
... = a * n + a + n + 1 : { add_assoc (a * n) a n }
... = a * n + a + n + 1 : { symm (add_assoc (a * n) a n) }
... = a * (n + 1) + n + 1 : { symm (mul_succr a n) }
... = a * (n + 1) + (n + 1) : symm (add_assoc (a * (n + 1)) n 1))
... = a * (n + 1) + (n + 1) : add_assoc (a * (n + 1)) n 1)
theorem mul_onel (a : Nat) : 1 * a = a
:= induction_on a
@ -148,12 +148,12 @@ theorem distributer (a b c : Nat) : a * (b + c) = a * b + a * c
(λ (n : Nat) (iH : n * (b + c) = n * b + n * c),
calc (n + 1) * (b + c) = n * (b + c) + (b + c) : mul_succl n (b + c)
... = n * b + n * c + (b + c) : { iH }
... = n * b + n * c + b + c : add_assoc (n * b + n * c) b c
... = n * b + (n * c + b) + c : { symm (add_assoc (n * b) (n * c) b) }
... = n * b + n * c + b + c : symm (add_assoc (n * b + n * c) b c)
... = n * b + (n * c + b) + c : { add_assoc (n * b) (n * c) b }
... = n * b + (b + n * c) + c : { add_comm (n * c) b }
... = n * b + b + n * c + c : { add_assoc (n * b) b (n * c) }
... = n * b + b + n * c + c : { symm (add_assoc (n * b) b (n * c)) }
... = (n + 1) * b + n * c + c : { symm (mul_succl n b) }
... = (n + 1) * b + (n * c + c) : symm (add_assoc ((n + 1) * b) (n * c) c)
... = (n + 1) * b + (n * c + c) : add_assoc ((n + 1) * b) (n * c) c
... = (n + 1) * b + (n + 1) * c : { symm (mul_succl n c) })
theorem distributel (a b c : Nat) : (a + b) * c = a * c + b * c
@ -162,8 +162,8 @@ theorem distributel (a b c : Nat) : (a + b) * c = a * c + b * c
... = a * c + c * b : { mul_comm c a }
... = a * c + b * c : { mul_comm c b }
theorem mul_assoc (a b c : Nat) : a * (b * c) = a * b * c
:= induction_on a
theorem mul_assoc (a b c : Nat) : (a * b) * c = a * (b * c)
:= symm (induction_on a
(calc 0 * (b * c) = 0 : mul_zerol (b * c)
... = 0 * c : symm (mul_zerol c)
... = (0 * b) * c : { symm (mul_zerol b) })
@ -171,7 +171,13 @@ theorem mul_assoc (a b c : Nat) : a * (b * c) = a * b * c
calc (n + 1) * (b * c) = n * (b * c) + (b * c) : mul_succl n (b * c)
... = n * b * c + (b * c) : { iH }
... = (n * b + b) * c : symm (distributel (n * b) b c)
... = (n + 1) * b * c : { symm (mul_succl n b) })
... = (n + 1) * b * c : { symm (mul_succl n b) }))
theorem add_left_comm (a b c : Nat) : a + (b + c) = b + (a + c)
:= left_comm add_comm add_assoc a b c
theorem mul_left_comm (a b c : Nat) : a * (b * c) = b * (a * c)
:= left_comm mul_comm mul_assoc a b c
theorem add_injr {a b c : Nat} : a + b = a + c → b = c
:= induction_on a
@ -181,13 +187,13 @@ theorem add_injr {a b c : Nat} : a + b = a + c → b = c
... = c : add_zerol c)
(λ (n : Nat) (iH : n + b = n + c → b = c) (H : n + 1 + b = n + 1 + c),
let L1 : n + b + 1 = n + c + 1
:= (calc n + b + 1 = n + (b + 1) : symm (add_assoc n b 1)
:= (calc n + b + 1 = n + (b + 1) : add_assoc n b 1
... = n + (1 + b) : { add_comm b 1 }
... = n + 1 + b : add_assoc n 1 b
... = n + 1 + b : symm (add_assoc n 1 b)
... = n + 1 + c : H
... = n + (1 + c) : symm (add_assoc n 1 c)
... = n + (1 + c) : add_assoc n 1 c
... = n + (c + 1) : { add_comm 1 c }
... = n + c + 1 : add_assoc n c 1),
... = n + c + 1 : symm (add_assoc n c 1)),
L2 : n + b = n + c := succ_inj L1
in iH L2)
@ -202,9 +208,9 @@ theorem add_eqz {a b : Nat} (H : a + b = 0) : a = 0
(λ (n : Nat) (H1 : a = n + 1),
absurd_elim (a = 0)
H (calc a + b = n + 1 + b : { H1 }
... = n + (1 + b) : symm (add_assoc n 1 b)
... = n + (1 + b) : add_assoc n 1 b
... = n + (b + 1) : { add_comm 1 b }
... = n + b + 1 : add_assoc n b 1
... = n + b + 1 : symm (add_assoc n b 1)
... ≠ 0 : succ_nz (n + b)))
theorem le_intro {a b c : Nat} (H : a + c = b) : a ≤ b
@ -221,22 +227,22 @@ theorem le_zero (a : Nat) : 0 ≤ a := le_intro (add_zerol a)
theorem le_trans {a b c : Nat} (H1 : a ≤ b) (H2 : b ≤ c) : a ≤ c
:= obtain (w1 : Nat) (Hw1 : a + w1 = b), from (le_elim H1),
obtain (w2 : Nat) (Hw2 : b + w2 = c), from (le_elim H2),
le_intro (calc a + (w1 + w2) = a + w1 + w2 : add_assoc a w1 w2
le_intro (calc a + (w1 + w2) = a + w1 + w2 : symm (add_assoc a w1 w2)
... = b + w2 : { Hw1 }
... = c : Hw2)
theorem le_add {a b : Nat} (H : a ≤ b) (c : Nat) : a + c ≤ b + c
:= obtain (w : Nat) (Hw : a + w = b), from (le_elim H),
le_intro (calc a + c + w = a + (c + w) : symm (add_assoc a c w)
le_intro (calc a + c + w = a + (c + w) : add_assoc a c w
... = a + (w + c) : { add_comm c w }
... = a + w + c : add_assoc a w c
... = a + w + c : symm (add_assoc a w c)
... = b + c : { Hw })
theorem le_antisym {a b : Nat} (H1 : a ≤ b) (H2 : b ≤ a) : a = b
:= obtain (w1 : Nat) (Hw1 : a + w1 = b), from (le_elim H1),
obtain (w2 : Nat) (Hw2 : b + w2 = a), from (le_elim H2),
let L1 : w1 + w2 = 0
:= add_injr (calc a + (w1 + w2) = a + w1 + w2 : { add_assoc a w1 w2 }
:= add_injr (calc a + (w1 + w2) = a + w1 + w2 : { symm (add_assoc a w1 w2) }
... = b + w2 : { Hw1 }
... = a : Hw2
... = a + 0 : symm (add_zeror a)),
@ -249,9 +255,9 @@ theorem not_lt_0 (a : Nat) : ¬ a < 0
:= not_intro (λ H : a + 1 ≤ 0,
obtain (w : Nat) (Hw1 : a + 1 + w = 0), from (le_elim H),
absurd
(calc a + w + 1 = a + (w + 1) : symm (add_assoc _ _ _)
(calc a + w + 1 = a + (w + 1) : add_assoc _ _ _
... = a + (1 + w) : { add_comm _ _ }
... = a + 1 + w : add_assoc _ _ _
... = a + 1 + w : symm (add_assoc _ _ _)
... = 0 : Hw1)
(succ_nz (a + w)))
@ -263,7 +269,7 @@ theorem lt_elim {a b : Nat} (H : a < b) : ∃ x, a + 1 + x = b
theorem lt_le {a b : Nat} (H : a < b) : a ≤ b
:= obtain (w : Nat) (Hw : a + 1 + w = b), from (le_elim H),
le_intro (calc a + (1 + w) = a + 1 + w : add_assoc _ _ _
le_intro (calc a + (1 + w) = a + 1 + w : symm (add_assoc _ _ _)
... = b : Hw)
theorem lt_ne {a b : Nat} (H : a < b) : a ≠ b
@ -271,7 +277,7 @@ theorem lt_ne {a b : Nat} (H : a < b) : a ≠ b
obtain (w : Nat) (Hw : a + 1 + w = b), from (lt_elim H),
absurd (calc w + 1 = 1 + w : add_comm _ _
... = 0 :
add_injr (calc b + (1 + w) = b + 1 + w : add_assoc b 1 w
add_injr (calc b + (1 + w) = b + 1 + w : symm (add_assoc b 1 w)
... = a + 1 + w : { symm H1 }
... = b : Hw
... = b + 0 : symm (add_zeror b)))
@ -284,40 +290,40 @@ theorem lt_nrefl (a : Nat) : ¬ a < a
theorem lt_trans {a b c : Nat} (H1 : a < b) (H2 : b < c) : a < c
:= obtain (w1 : Nat) (Hw1 : a + 1 + w1 = b), from (lt_elim H1),
obtain (w2 : Nat) (Hw2 : b + 1 + w2 = c), from (lt_elim H2),
lt_intro (calc a + 1 + (w1 + 1 + w2) = a + 1 + (w1 + (1 + w2)) : { symm (add_assoc w1 1 w2) }
... = (a + 1 + w1) + (1 + w2) : add_assoc _ _ _
lt_intro (calc a + 1 + (w1 + 1 + w2) = a + 1 + (w1 + (1 + w2)) : { add_assoc w1 1 w2 }
... = (a + 1 + w1) + (1 + w2) : symm (add_assoc _ _ _)
... = b + (1 + w2) : { Hw1 }
... = b + 1 + w2 : add_assoc _ _ _
... = b + 1 + w2 : symm (add_assoc _ _ _)
... = c : Hw2)
theorem lt_le_trans {a b c : Nat} (H1 : a < b) (H2 : b ≤ c) : a < c
:= obtain (w1 : Nat) (Hw1 : a + 1 + w1 = b), from (lt_elim H1),
obtain (w2 : Nat) (Hw2 : b + w2 = c), from (le_elim H2),
lt_intro (calc a + 1 + (w1 + w2) = a + 1 + w1 + w2 : add_assoc _ _ _
lt_intro (calc a + 1 + (w1 + w2) = a + 1 + w1 + w2 : symm (add_assoc _ _ _)
... = b + w2 : { Hw1 }
... = c : Hw2)
theorem le_lt_trans {a b c : Nat} (H1 : a ≤ b) (H2 : b < c) : a < c
:= obtain (w1 : Nat) (Hw1 : a + w1 = b), from (le_elim H1),
obtain (w2 : Nat) (Hw2 : b + 1 + w2 = c), from (lt_elim H2),
lt_intro (calc a + 1 + (w1 + w2) = a + 1 + w1 + w2 : add_assoc _ _ _
... = a + (1 + w1) + w2 : { symm (add_assoc a 1 w1) }
lt_intro (calc a + 1 + (w1 + w2) = a + 1 + w1 + w2 : symm (add_assoc _ _ _)
... = a + (1 + w1) + w2 : { add_assoc a 1 w1 }
... = a + (w1 + 1) + w2 : { add_comm 1 w1 }
... = a + w1 + 1 + w2 : { add_assoc a w1 1 }
... = a + w1 + 1 + w2 : { symm (add_assoc a w1 1) }
... = b + 1 + w2 : { Hw1 }
... = c : Hw2)
theorem ne_lt_succ {a b : Nat} (H1 : a ≠ b) (H2 : a < b + 1) : a < b
:= obtain (w : Nat) (Hw : a + 1 + w = b + 1), from (lt_elim H2),
let L : a + w = b := add_injl (calc a + w + 1 = a + (w + 1) : symm (add_assoc _ _ _)
let L : a + w = b := add_injl (calc a + w + 1 = a + (w + 1) : add_assoc _ _ _
... = a + (1 + w) : { add_comm _ _ }
... = a + 1 + w : add_assoc _ _ _
... = a + 1 + w : symm (add_assoc _ _ _)
... = b + 1 : Hw)
in discriminate (λ Hz : w = 0, absurd_elim (a < b) (calc a = a + 0 : symm (add_zeror _)
... = a + w : { symm Hz }
... = b : L)
H1)
(λ (p : Nat) (Hp : w = p + 1), lt_intro (calc a + 1 + p = a + (1 + p) : symm (add_assoc _ _ _)
(λ (p : Nat) (Hp : w = p + 1), lt_intro (calc a + 1 + p = a + (1 + p) : add_assoc _ _ _
... = a + (p + 1) : { add_comm _ _ }
... = a + w : { symm Hp }
... = b : L))

Binary file not shown.

View file

@ -34,6 +34,8 @@ MK_CONSTANT(Nat_mul_comm_fn, name({"Nat", "mul_comm"}));
MK_CONSTANT(Nat_distributer_fn, name({"Nat", "distributer"}));
MK_CONSTANT(Nat_distributel_fn, name({"Nat", "distributel"}));
MK_CONSTANT(Nat_mul_assoc_fn, name({"Nat", "mul_assoc"}));
MK_CONSTANT(Nat_add_left_comm_fn, name({"Nat", "add_left_comm"}));
MK_CONSTANT(Nat_mul_left_comm_fn, name({"Nat", "mul_left_comm"}));
MK_CONSTANT(Nat_add_injr_fn, name({"Nat", "add_injr"}));
MK_CONSTANT(Nat_add_injl_fn, name({"Nat", "add_injl"}));
MK_CONSTANT(Nat_add_eqz_fn, name({"Nat", "add_eqz"}));

View file

@ -92,6 +92,12 @@ inline expr mk_Nat_distributel_th(expr const & e1, expr const & e2, expr const &
expr mk_Nat_mul_assoc_fn();
bool is_Nat_mul_assoc_fn(expr const & e);
inline expr mk_Nat_mul_assoc_th(expr const & e1, expr const & e2, expr const & e3) { return mk_app({mk_Nat_mul_assoc_fn(), e1, e2, e3}); }
expr mk_Nat_add_left_comm_fn();
bool is_Nat_add_left_comm_fn(expr const & e);
inline expr mk_Nat_add_left_comm_th(expr const & e1, expr const & e2, expr const & e3) { return mk_app({mk_Nat_add_left_comm_fn(), e1, e2, e3}); }
expr mk_Nat_mul_left_comm_fn();
bool is_Nat_mul_left_comm_fn(expr const & e);
inline expr mk_Nat_mul_left_comm_th(expr const & e1, expr const & e2, expr const & e3) { return mk_app({mk_Nat_mul_left_comm_fn(), e1, e2, e3}); }
expr mk_Nat_add_injr_fn();
bool is_Nat_add_injr_fn(expr const & e);
inline expr mk_Nat_add_injr_th(expr const & e1, expr const & e2, expr const & e3, expr const & e4) { return mk_app({mk_Nat_add_injr_fn(), e1, e2, e3, e4}); }

View file

@ -6,16 +6,16 @@
9
2 + 2 + (2 + 2) + 1 ≥ 3
3 ≤ 2 * 2 + 2 * 2 + 2 * 2 + 2 * 2 + 1
3 ≤ 2 * 2 + (2 * 2 + (2 * 2 + (2 * 2 + 1)))
Assumed: a
Assumed: b
Assumed: c
Assumed: d
Imported 'if_then_else'
a * c + a * d + b * c + b * d
a * c + (a * d + (b * c + b * d))
trans (Nat::distributel a b (c + d))
(trans (congr (congr2 Nat::add (Nat::distributer a c d)) (Nat::distributer b c d))
(Nat::add_assoc (a * c + a * d) (b * c) (b * d)))
(Nat::add_assoc (a * c) (a * d) (b * c + b * d)))
Proved: congr2_congr1
Proved: congr2_congr2
Proved: congr1_congr2
@ -28,7 +28,7 @@ trans (congr (congr2 eq
let κ::1 := congr2 (λ x : , eq ((λ x : , x + 10) x))
(trans (congr2 (ite (a > 0) b) (Nat::add_zeror b)) (if_a_a (a > 0) b))
in trans (congr κ::1 (congr2 (λ x : , x + 10) (if_a_a (a > 0) b))) (eq_id (b + 10))
a * a + a * b + b * a + b * b
a * a + (a * b + (b * a + b * b))
→ ⊥ refl ( → ⊥)
refl ()
⊥ → ⊥ refl (⊥ → ⊥)

10
tests/lean/simp8.lean Normal file
View file

@ -0,0 +1,10 @@
variables a b c d e f : Nat
rewrite_set simple
add_rewrite Nat::add_assoc Nat::add_comm Nat::add_left_comm Nat::distributer Nat::distributel : simple
(*
local t = parse_lean("f + (c + f + d) + (e * (a + c) + (d + a))")
local t2, pr = simplify(t, "simple")
print(t)
print("====>")
print(t2)
*)

View file

@ -0,0 +1,11 @@
Set: pp::colors
Set: pp::unicode
Assumed: a
Assumed: b
Assumed: c
Assumed: d
Assumed: e
Assumed: f
f + (c + f + d) + (e * (a + c) + (d + a))
====>
a + (c + (d + (d + (f + (f + (e * a + e * c))))))

View file

@ -2,7 +2,7 @@
Set: pp::unicode
Using: Nat
0 + 1
Nat::add_assoc : ∀ a b c : , a + (b + c) = a + b + c
Nat::add_assoc : ∀ a b c : , a + b + c = a + (b + c)
using.lean:7:6: error: unknown identifier 'add'
Using: Nat
0 + 1