Package word16: 16-bit words

Information

name	word16
version	1.35
description	16-bit words
author	Joe Hurd <joe@gilith.com>
license	MIT
requires	bool pair natural list natural-divides byte
show	Data.Bool Data.Byte Data.Byte.Bits Data.List Data.Pair Data.Word16 Data.Word16.Bits Number.Natural

Files

Package tarball word16-1.35.tgz
Theory file word16.thy (included in the package tarball)

Defined Type Operator

Data
- Word16
  - word16

Defined Constants

Data
- Word16
  - *
  - +
  - -
  - <
  - ≤
  - ~
  - and
  - bit
  - fromBytes
  - fromNatural
  - modulus
  - not
  - or
  - shiftLeft
  - shiftRight
  - toBytes
  - toNatural
  - width
  - Bits
    - compare
    - fromWord
    - normal
    - toWord

Theorems

⊦ ¬(modulus = 0)

⊦ ∀w. normal (fromWord w)

⊦ ∀w. w ≤ w

⊦ fromNatural modulus = 0

⊦ toWord [] = 0

⊦ toNatural (toWord []) = 0

⊦ modulus mod modulus = 0

⊦ 0 mod modulus = 0

⊦ ∀w. ¬(w < w)

⊦ ∀x. toNatural x < modulus

⊦ ~0 = 0

⊦ ∀x. ~~x = x

⊦ ∀x. fromNatural (toNatural x) = x

⊦ ∀w. toWord (fromWord w) = w

⊦ ∀w. length (fromWord w) = width

⊦ ∀n. n mod modulus < modulus

⊦ modulus = exp 2 width

⊦ ∀q. compare q [] [] ⇔ q

⊦ ∀x. x + 0 = x

⊦ ∀x. 0 + x = x

⊦ ∀x. toNatural x div modulus = 0

⊦ width = 16

⊦ ∀b. fromNatural (toNatural b) = toWord (fromByte b)

⊦ ∀w. fromNatural (toNatural w) = toByte (fromWord w)

⊦ ∀x. x * 0 = 0

⊦ ∀x. x + ~x = 0

⊦ ∀x. 0 * x = 0

⊦ ∀x. ~x + x = 0

⊦ ∀x. toNatural x mod modulus = toNatural x

⊦ ∀x. x * 1 = x

⊦ ∀x. 1 * x = x

⊦ ∀x. toNatural (fromNatural x) = x mod modulus

⊦ ∀l. normal l ⇔ length l = width

⊦ ∀w. ∃b0 b1. w = fromBytes b0 b1

⊦ ∀x. ~x = fromNatural (modulus - toNatural x)

⊦ ∀w. not w = toWord (map (¬) (fromWord w))

⊦ ∀x y. x * y = y * x

⊦ ∀x y. x + y = y + x

⊦ ∀w. fromWord w = map (bit w) (interval 0 width)

⊦ ∀n. divides modulus n ⇔ n mod modulus = 0

⊦ ∀n. n < modulus ⇒ n mod modulus = n

⊦ ∀x. fromNatural x = 0 ⇔ divides modulus x

⊦ ∀n. n mod modulus mod modulus = n mod modulus

⊦ ∀x y. x < y ⇔ ¬(y ≤ x)

⊦ ∀x y. x - y = x + ~y

⊦ ∀x. ~x = 0 ⇔ x = 0

⊦ ∀l. toNatural (toWord l) < exp 2 (length l)

⊦ ∀l. length l = width ⇔ fromWord (toWord l) = l

⊦ ∀x y. x < y ⇔ toNatural x < toNatural y

⊦ ∀x y. x ≤ y ⇔ toNatural x ≤ toNatural y

⊦ ∀x y. x * ~y = ~(x * y)

⊦ ∀x y. ~x * y = ~(x * y)

⊦ ∀w1 w2. fromWord w1 = fromWord w2 ⇔ w1 = w2

⊦ ∀x y. ~x = ~y ⇒ x = y

⊦ ∀x y. toNatural x = toNatural y ⇒ x = y

⊦ ∀w1 w2. fromWord w1 = fromWord w2 ⇒ w1 = w2

⊦ ∀w n. bit w n ⇔ odd (toNatural (shiftRight w n))

⊦ ∀b0 b1. toWord (fromByte b1 @ fromByte b0) = fromBytes b0 b1

⊦ ∀x y. x + y = x ⇔ y = 0

⊦ ∀x y. y + x = x ⇔ y = 0

⊦ ∀x y. ~x + ~y = ~(x + y)

⊦ ∀w1 w2. compare F (fromWord w1) (fromWord w2) ⇔ w1 < w2

⊦ ∀w1 w2. compare T (fromWord w1) (fromWord w2) ⇔ w1 ≤ w2

⊦ ∀x1 y1. fromNatural (x1 * y1) = fromNatural x1 * fromNatural y1

⊦ ∀x1 y1. fromNatural (x1 + y1) = fromNatural x1 + fromNatural y1

⊦ ∀l. width ≤ length l ⇒ fromWord (toWord l) = take width l

⊦ ∀w1 w2. and w1 w2 = toWord (zipWith (∧) (fromWord w1) (fromWord w2))

⊦ ∀w1 w2. or w1 w2 = toWord (zipWith (∨) (fromWord w1) (fromWord w2))

⊦ ∀l n. shiftLeft (toWord l) n = toWord (replicate n F @ l)

⊦ ∀x y. toNatural (x * y) = toNatural x * toNatural y mod modulus

⊦ ∀x y. toNatural (x + y) = (toNatural x + toNatural y) mod modulus

⊦ ∀x y z. x * y * z = x * (y * z)

⊦ ∀x y z. x + y + z = x + (y + z)

⊦ ∀x y z. x + y = x + z ⇔ y = z

⊦ ∀x y z. y + x = z + x ⇔ y = z

⊦ ∀w1 w2 w3. w1 < w2 ∧ w2 < w3 ⇒ w1 < w3

⊦ ∀w1 w2 w3. w1 < w2 ∧ w2 ≤ w3 ⇒ w1 < w3

⊦ ∀w1 w2 w3. w1 ≤ w2 ∧ w2 < w3 ⇒ w1 < w3

⊦ ∀w1 w2 w3. w1 ≤ w2 ∧ w2 ≤ w3 ⇒ w1 ≤ w3

⊦ ∀n. toWord (odd n :: fromWord (fromNatural (n div 2))) = fromNatural n

⊦ ∀w n. bit w n ⇔ odd (toNatural w div exp 2 n)

⊦ ∀w n. shiftLeft w n = fromNatural (exp 2 n * toNatural w)

⊦ ∀w n. shiftRight w n = fromNatural (toNatural w div exp 2 n)

⊦ ∀x y. fromNatural x = fromNatural y ⇔ x mod modulus = y mod modulus

⊦ ∀w. ∃b0 b1. w = fromBytes b0 b1 ∧ toBytes w = (b0, b1)

⊦ ∀x y z. x * (y + z) = x * y + x * z

⊦ ∀x y z. (y + z) * x = y * x + z * x

⊦ ∀m n. m mod modulus * (n mod modulus) mod modulus = m * n mod modulus

⊦ ∀m n. (m mod modulus + n mod modulus) mod modulus = (m + n) mod modulus

⊦ ∀l.
length l ≤ width ⇒
fromWord (toWord l) = l @ replicate (width - length l) F

⊦ ∀q w1 w2.
compare q (fromWord w1) (fromWord w2) ⇔ if q then w1 ≤ w2 else w1 < w2

⊦ ∀w1 w2. (∀i. i < width ⇒ (bit w1 i ⇔ bit w2 i)) ⇒ w1 = w2

⊦ ∀l. 2 * toNatural (toWord l) + 1 < exp 2 (suc (length l))

⊦ ∀b1 b2.
    fromBytes b1 b2 =
    or (shiftLeft (fromNatural (toNatural b1)) 8)
      (fromNatural (toNatural b2))

⊦ ∀x y. x < modulus ∧ y < modulus ∧ fromNatural x = fromNatural y ⇒ x = y

⊦ ∀l n. bit (toWord l) n ⇔ n < width ∧ n < length l ∧ nth n l

⊦ ∀n.
    fromNatural n =
    toWord
      (if n = 0 then [] else odd n :: fromWord (fromNatural (n div 2)))

⊦ ∀l.
    fromWord (toWord l) =
    if length l ≤ width then l @ replicate (width - length l) F
    else take width l

⊦ ∀w.
(toByte (drop 8 (fromWord w)), toByte (take 8 (fromWord w))) =
toBytes w

⊦ ∀h t.
toWord (h :: t) =
if h then shiftLeft (toWord t) 1 + 1 else shiftLeft (toWord t) 1

⊦ ∀h t.
toNatural (toWord (h :: t)) =
(2 * toNatural (toWord t) + if h then 1 else 0) mod modulus

⊦ ∀h t.
2 * toNatural (toWord t) + (if h then 1 else 0) <
exp 2 (suc (length t))

⊦ ∀l n.
    length l ≤ width ⇒
    shiftRight (toWord l) n =
    if length l ≤ n then toWord [] else toWord (drop n l)

⊦ ∀l n.
    width ≤ length l ⇒
    shiftRight (toWord l) n =
    if width ≤ n then toWord [] else toWord (drop n (take width l))

⊦ ∀w.
    toBytes w =
    (fromNatural (toNatural (shiftRight w 8)),
     fromNatural (toNatural (and w 255)))

⊦ ∀q h1 h2 t1 t2.
compare q (h1 :: t1) (h2 :: t2) ⇔
compare (¬h1 ∧ h2 ∨ ¬(h1 ∧ ¬h2) ∧ q) t1 t2

⊦ ∀l n.
    shiftRight (toWord l) n =
    if length l ≤ width then
      if length l ≤ n then toWord [] else toWord (drop n l)
    else if width ≤ n then toWord []
    else toWord (drop n (take width l))

⊦ ∀w.
    ∃x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 x10 x11 x12 x13 x14 x15.
      w =
      toWord
        (x0 :: x1 :: x2 :: x3 :: x4 :: x5 :: x6 :: x7 :: x8 :: x9 :: x10 ::
         x11 :: x12 :: x13 :: x14 :: x15 :: [])

Input Type Operators

→
bool
Data
- Byte
  - byte
- List
  - list
- Pair
  - ×
Number
- Natural
  - natural

Input Constants

=
select
Data
- Bool
  - ∀
  - ∧
  - ⇒
  - ∃
  - ∨
  - ¬
  - cond
  - F
  - T
- Byte
  - bit
  - fromNatural
  - modulus
  - toNatural
  - width
  - Bits
    - fromByte
    - toByte
- List
  - ::
  - @
  - []
  - drop
  - head
  - interval
  - length
  - map
  - nth
  - replicate
  - tail
  - take
  - zipWith
- Pair
  - ,
  - fst
  - snd
Number
- Natural
  - *
  - +
  - -
  - <
  - ≤
  - bit0
  - bit1
  - div
  - divides
  - even
  - exp
  - mod
  - odd
  - suc
  - zero

Assumptions

⊦ T

⊦ ¬F ⇔ T

⊦ ¬T ⇔ F

⊦ even 0 ⇔ T

⊦ odd 0 ⇔ F

⊦ length [] = 0

⊦ bit0 0 = 0

⊦ ∀x. x = x

⊦ ∀t. t ⇒ t

⊦ ∀n. 0 ≤ n

⊦ ∀n. n ≤ n

⊦ F ⇔ ∀p. p

⊦ ∀t. t ∨ ¬t

⊦ ∀n. 0 < suc n

⊦ ∀n. n < suc n

⊦ ∀n. n ≤ suc n

⊦ (¬) = λp. p ⇒ F

⊦ (∃) = λP. P ((select) P)

⊦ ∀t. (∀x. t) ⇔ t

⊦ ∀t. (λx. t x) = t

⊦ (∀) = λp. p = λx. T

⊦ ∀x. replicate 0 x = []

⊦ ∀t. ¬¬t ⇔ t

⊦ ∀t. (T ⇔ t) ⇔ t

⊦ ∀t. (t ⇔ T) ⇔ t

⊦ ∀t. F ∧ t ⇔ F

⊦ ∀t. T ∧ t ⇔ t

⊦ ∀t. t ∧ F ⇔ F

⊦ ∀t. t ∧ T ⇔ t

⊦ ∀t. t ∧ t ⇔ t

⊦ ∀t. F ⇒ t ⇔ T

⊦ ∀t. T ⇒ t ⇔ t

⊦ ∀t. t ⇒ T ⇔ T

⊦ ∀t. F ∨ t ⇔ t

⊦ ∀t. T ∨ t ⇔ T

⊦ ∀t. t ∨ F ⇔ t

⊦ ∀t. t ∨ T ⇔ T

⊦ ∀w. toByte (fromByte w) = w

⊦ ∀w. length (fromByte w) = width

⊦ ∀n. ¬(suc n = 0)

⊦ ∀n. even n ∨ odd n

⊦ ∀m. m < 0 ⇔ F

⊦ ∀n. 0 * n = 0

⊦ ∀m. m * 0 = 0

⊦ ∀n. 0 + n = n

⊦ ∀m. m + 0 = m

⊦ ∀m. m - 0 = m

⊦ ∀n. n - n = 0

⊦ ∀m. interval m 0 = []

⊦ ∀l. [] @ l = l

⊦ ∀l. drop 0 l = l

⊦ ∀l. take 0 l = []

⊦ ∀f. map f [] = []

⊦ modulus = exp 2 width

⊦ width = 8

⊦ ∀t. (F ⇔ t) ⇔ ¬t

⊦ ∀t. (t ⇔ F) ⇔ ¬t

⊦ ∀t. t ⇒ F ⇔ ¬t

⊦ ∀n. even (2 * n)

⊦ ∀n. bit1 n = suc (bit0 n)

⊦ ∀n. ¬even n ⇔ odd n

⊦ ∀n. ¬odd n ⇔ even n

⊦ ∀m. exp m 0 = 1

⊦ ∀m. m * 1 = m

⊦ ∀n. n div 1 = n

⊦ ∀n. exp n 1 = n

⊦ ∀n. n mod 1 = 0

⊦ ∀m. 1 * m = m

⊦ ∀l. take (length l) l = l

⊦ ∀f. zipWith f [] [] = []

⊦ ∀m n. m ≤ m + n

⊦ ∀m n. n ≤ m + n

⊦ (⇒) = λp q. p ∧ q ⇔ p

⊦ ∀t. (t ⇔ T) ∨ (t ⇔ F)

⊦ ∀n. odd (suc (2 * n))

⊦ ∀m. suc m = m + 1

⊦ ∀n. even (suc n) ⇔ ¬even n

⊦ ∀n. odd (suc n) ⇔ ¬odd n

⊦ ∀m. m ≤ 0 ⇔ m = 0

⊦ ∀x. toNatural (fromNatural x) = x mod modulus

⊦ ∀x. (fst x, snd x) = x

⊦ ∀t1 t2. (if F then t1 else t2) = t2

⊦ ∀t1 t2. (if T then t1 else t2) = t1

⊦ ∀x y. fst (x, y) = x

⊦ ∀x y. snd (x, y) = y

⊦ ∀h t. head (h :: t) = h

⊦ ∀h t. tail (h :: t) = t

⊦ ∀n x. length (replicate n x) = n

⊦ ∀m n. length (interval m n) = n

⊦ ∀n. 0 < n ⇔ ¬(n = 0)

⊦ ∀n. bit0 (suc n) = suc (suc (bit0 n))

⊦ ∀l. length l = 0 ⇔ l = []

⊦ ∀x y. x = y ⇔ y = x

⊦ ∀x y. x = y ⇒ y = x

⊦ ∀h t. nth 0 (h :: t) = h

⊦ ∀t1 t2. t1 ∧ t2 ⇔ t2 ∧ t1

⊦ ∀t1 t2. t1 ∨ t2 ⇔ t2 ∨ t1

⊦ ∀m n. m * n = n * m

⊦ ∀m n. m + n = n + m

⊦ ∀m n. m = n ⇒ m ≤ n

⊦ ∀m n. m < n ⇒ m ≤ n

⊦ ∀m n. m ≤ n ∨ n ≤ m

⊦ ∀m n. m + n - m = n

⊦ ∀m n. m + n - n = m

⊦ ∀l f. length (map f l) = length l

⊦ ∀n. 2 * n = n + n

⊦ ∀h t. length (h :: t) = suc (length t)

⊦ ∀m n. ¬(m < n ∧ n ≤ m)

⊦ ∀m n. ¬(m ≤ n ∧ n < m)

⊦ ∀m n. ¬(m < n) ⇔ n ≤ m

⊦ ∀m n. ¬(m ≤ n) ⇔ n < m

⊦ ∀m n. m < suc n ⇔ m ≤ n

⊦ ∀m n. suc m ≤ n ⇔ m < n

⊦ ∀m. m = 0 ∨ ∃n. m = suc n

⊦ (∧) = λp q. (λf. f p q) = λf. f T T

⊦ ∀n. even n ⇔ n mod 2 = 0

⊦ ∀n. ¬(n = 0) ⇒ 0 mod n = 0

⊦ ∀n. ¬(n = 0) ⇒ n mod n = 0

⊦ ∀P. ¬(∀x. P x) ⇔ ∃x. ¬P x

⊦ (∃) = λP. ∀q. (∀x. P x ⇒ q) ⇒ q

⊦ ∀t1 t2. ¬t1 ⇒ ¬t2 ⇔ t2 ⇒ t1

⊦ ∀w1 w2. fromByte w1 = fromByte w2 ⇔ w1 = w2

⊦ ∀m n. m < n ⇒ m div n = 0

⊦ ∀m n. m < n ⇒ m mod n = m

⊦ ∀m n. m + suc n = suc (m + n)

⊦ ∀m n. suc m + n = suc (m + n)

⊦ ∀m n. m < m + n ⇔ 0 < n

⊦ ∀m n. suc m = suc n ⇔ m = n

⊦ ∀m n. suc m < suc n ⇔ m < n

⊦ ∀m n. suc m ≤ suc n ⇔ m ≤ n

⊦ ∀m n. m + n = m ⇔ n = 0

⊦ ∀n. odd n ⇔ n mod 2 = 1

⊦ ∀x n. replicate (suc n) x = x :: replicate n x

⊦ ∀m n. even (m * n) ⇔ even m ∨ even n

⊦ ∀m n. even (m + n) ⇔ even m ⇔ even n

⊦ ∀m n. m * suc n = m + m * n

⊦ ∀m n. exp m (suc n) = m * exp m n

⊦ ∀m n. suc m * n = m * n + n

⊦ ∀m n. ¬(n = 0) ⇒ m mod n < n

⊦ ∀m n. ¬(n = 0) ⇒ m div n ≤ m

⊦ ∀m n. ¬(n = 0) ⇒ m mod n ≤ m

⊦ ∀l m. length (l @ m) = length l + length m

⊦ ∀m n. m ≤ n ⇔ ∃d. n = m + d

⊦ ∀l. l = [] ∨ ∃h t. l = h :: t

⊦ ∀f g. (∀x. f x = g x) ⇔ f = g

⊦ (∨) = λp q. ∀r. (p ⇒ r) ⇒ (q ⇒ r) ⇒ r

⊦ ∀m n. m ≤ n ⇔ m < n ∨ m = n

⊦ ∀m n. n ≤ m ⇒ n + (m - n) = m

⊦ ∀m n. n ≤ m ⇒ m - n + n = m

⊦ ∀m n. odd (m + n) ⇔ ¬(odd m ⇔ odd n)

⊦ ∀m n. interval m (suc n) = m :: interval (suc m) n

⊦ ∀m n. m ≤ n ∧ n ≤ m ⇔ m = n

⊦ ∀n l. n ≤ length l ⇒ length (take n l) = n

⊦ ∀P. (∀x y. P x y) ⇔ ∀y x. P x y

⊦ ∀P Q. P ∨ (∃x. Q x) ⇔ ∃x. P ∨ Q x

⊦ ∀m n. ¬(m = 0) ⇒ m * n div m = n

⊦ ∀m n. ¬(m = 0) ⇒ m * n mod m = 0

⊦ ∀x y z. x = y ∧ y = z ⇒ x = z

⊦ ∀t1 t2 t3. (t1 ∧ t2) ∧ t3 ⇔ t1 ∧ t2 ∧ t3

⊦ ∀t1 t2 t3. (t1 ∨ t2) ∨ t3 ⇔ t1 ∨ t2 ∨ t3

⊦ ∀n x i. i < n ⇒ nth i (replicate n x) = x

⊦ ∀m n p. m * (n * p) = m * n * p

⊦ ∀m n p. m + (n + p) = m + n + p

⊦ ∀m n p. m + n < m + p ⇔ n < p

⊦ ∀m n p. n + m < p + m ⇔ n < p

⊦ ∀m n p. m + n ≤ m + p ⇔ n ≤ p

⊦ ∀m n p. m < n ∧ n < p ⇒ m < p

⊦ ∀m n p. m < n ∧ n ≤ p ⇒ m < p

⊦ ∀m n p. m ≤ n ∧ n < p ⇒ m < p

⊦ ∀m n p. m ≤ n ∧ n ≤ p ⇒ m ≤ p

⊦ ∀l h t. (h :: t) @ l = h :: t @ l

⊦ ∀P. (∀x. ∃y. P x y) ⇔ ∃y. ∀x. P x (y x)

⊦ ∀w n. bit w n ⇔ odd (toNatural w div exp 2 n)

⊦ ∀m n. n < m ⇒ suc (m - suc n) = m - n

⊦ ∀m n. n ≤ m ⇒ (m - n = 0 ⇔ m = n)

⊦ ∀m n. m ≤ suc n ⇔ m = suc n ∨ m ≤ n

⊦ ∀m n. m * n = 0 ⇔ m = 0 ∨ n = 0

⊦ ∀f h t. map f (h :: t) = f h :: map f t

⊦ ∀P. P 0 ∧ (∀n. P n ⇒ P (suc n)) ⇒ ∀n. P n

⊦ ∀a b. ¬(a = 0) ⇒ (divides a b ⇔ b mod a = 0)

⊦ ∀m n. ¬(n = 0) ⇒ (m div n = 0 ⇔ m < n)

⊦ ∀m n. ¬(n = 0) ⇒ m mod n mod n = m mod n

⊦ ∀m n. exp m n = 0 ⇔ m = 0 ∧ ¬(n = 0)

⊦ ∀m n i. i < n ⇒ nth i (interval m n) = m + i

⊦ ∀m n p. m * (n + p) = m * n + m * p

⊦ ∀m n p. exp m (n + p) = exp m n * exp m p

⊦ ∀m n p. (m + n) * p = m * p + n * p

⊦ ∀P Q. (∀x. P x ∧ Q x) ⇔ (∀x. P x) ∧ ∀x. Q x

⊦ ∀P Q. (∃x. P x) ∨ (∃x. Q x) ⇔ ∃x. P x ∨ Q x

⊦ ∀m n. ¬(n = 0) ⇒ m div n * n + m mod n = m

⊦ ∀P. P [] ∧ (∀a0 a1. P a1 ⇒ P (a0 :: a1)) ⇒ ∀x. P x

⊦ ∀h t n. n < length t ⇒ nth (suc n) (h :: t) = nth n t

⊦ ∀w1 w2. (∀i. i < width ⇒ (bit w1 i ⇔ bit w2 i)) ⇒ w1 = w2

⊦ ∀n h t. n ≤ length t ⇒ drop (suc n) (h :: t) = drop n t

⊦ ∀m n p. m * n = m * p ⇔ m = 0 ∨ n = p

⊦ ∀m n p. m * n ≤ m * p ⇔ m = 0 ∨ n ≤ p

⊦ ∀f l i. i < length l ⇒ nth i (map f l) = f (nth i l)

⊦ ∀l n. bit (toByte l) n ⇔ n < width ∧ n < length l ∧ nth n l

⊦ ∀m n p. m * n < m * p ⇔ ¬(m = 0) ∧ n < p

⊦ ∀h1 h2 t1 t2. h1 :: t1 = h2 :: t2 ⇔ h1 = h2 ∧ t1 = t2

⊦ ∀x y a b. (x, y) = (a, b) ⇔ x = a ∧ y = b

⊦ ∀n h t. n ≤ length t ⇒ take (suc n) (h :: t) = h :: take n t

⊦ ∀l.
    fromByte (toByte l) =
    if length l ≤ width then l @ replicate (width - length l) F
    else take width l

⊦ ∀NIL' CONS'.
∃fn. fn [] = NIL' ∧ ∀a0 a1. fn (a0 :: a1) = CONS' a0 a1 (fn a1)

⊦ ∀m n p. ¬(n = 0) ⇒ m * (p mod n) mod n = m * p mod n

⊦ ∀m n p. ¬(n * p = 0) ⇒ m div n div p = m div (n * p)

⊦ ∀m n p. ¬(n * p = 0) ⇒ m mod (n * p) mod n = m mod n

⊦ ∀n l i. n ≤ length l ∧ i < n ⇒ nth i (take n l) = nth i l

⊦ ∀m n q r. m = q * n + r ∧ r < n ⇒ m div n = q

⊦ ∀m n q r. m = q * n + r ∧ r < n ⇒ m mod n = r

⊦ ∀m n p. ¬(n = 0) ⇒ m mod n * (p mod n) mod n = m * p mod n

⊦ ∀a b n. ¬(n = 0) ⇒ (a mod n + b mod n) mod n = (a + b) mod n

⊦ ∀m n p. ¬(n * p = 0) ⇒ m div n mod p = m mod (n * p) div n

⊦ ∀l m.
length l = length m ∧ (∀i. i < length l ⇒ nth i l = nth i m) ⇒ l = m

⊦ ∀f h1 h2 t1 t2.
length t1 = length t2 ⇒
zipWith f (h1 :: t1) (h2 :: t2) = f h1 h2 :: zipWith f t1 t2

⊦ ∀x m n.
exp x m ≤ exp x n ⇔ if x = 0 then m = 0 ⇒ n = 0 else x = 1 ∨ m ≤ n

⊦ ∀k l m.
k < length l + length m ⇒
nth k (l @ m) = if k < length l then nth k l else nth (k - length l) m

⊦ ∀b.
∃x0 x1 x2 x3 x4 x5 x6 x7.
b = toByte (x0 :: x1 :: x2 :: x3 :: x4 :: x5 :: x6 :: x7 :: [])

⊦ ∀a b n.
¬(n = 0) ⇒
((a + b) mod n = a mod n + b mod n ⇔ (a + b) div n = a div n + b div n)