IdrisDoc: Prelude.Nat

# Prelude.Nat

toIntegerNat : Nat -> Integer

  Convert a Nat to an Integer

toIntNat : Nat -> Int

  Cast Nat to Int
  Note that this can overflow

succNotLTEzero : Not (LTE (S m) 0)

  A successor is never less than or equal zero

succInjective : (left : Nat) -> (right : Nat) -> (p : S left = S right) -> left = right

  S is injective

sucMinR : (l : Nat) -> minimum l (S l) = l
sucMinL : (l : Nat) -> minimum (S l) l = l
sucMaxR : (l : Nat) -> maximum l (S l) = S l
sucMaxL : (l : Nat) -> maximum (S l) l = S l
predSucc : (n : Nat) -> pred (S n) = n
pred : Nat -> Nat

  The predecessor of a natural number. `pred Z` is `Z`.

powerZeroOne : (base : Nat) -> power base (fromInteger 0) = 1
powerSuccSuccMult : (base : Nat) -> power base (fromInteger 2) = mult base base
powerSuccPowerLeft : (base : Nat) -> (exp : Nat) -> power base (S exp) = base * power base exp
powerPowerMultPower : (base : Nat) -> (exp : Nat) -> (exp' : Nat) -> power (power base exp) exp' = power base (exp * exp')
powerOneSuccOne : (exp : Nat) -> power (fromInteger 1) exp = 1
powerOneNeutral : (base : Nat) -> power base (fromInteger 1) = base
power : Nat -> Nat -> Nat

  Exponentiation of natural numbers

plusZeroRightNeutral : (left : Nat) -> left + fromInteger 0 = left
plusZeroLeftNeutral : (right : Nat) -> fromInteger 0 + right = right
plusSuccRightSucc : (left : Nat) -> (right : Nat) -> S (left + right) = left + S right
plusRightCancel : (left : Nat) -> (left' : Nat) -> (right : Nat) -> (p : left + right = left' + right) -> left = left'
plusOneSucc : (right : Nat) -> fromInteger 1 + right = S right
plusMinusLeftCancel : (left : Nat) -> (right : Nat) -> (right' : Nat) -> minus (left + right) (left + right') = minus right right'
plusLeftLeftRightZero : (left : Nat) -> (right : Nat) -> (p : left + right = left) -> right = 0
plusLeftCancel : (left : Nat) -> (right : Nat) -> (right' : Nat) -> (p : left + right = left + right') -> right = right'
plusConstantRight : (left : Nat) -> (right : Nat) -> (c : Nat) -> (p : left = right) -> left + c = right + c
plusConstantLeft : (left : Nat) -> (right : Nat) -> (c : Nat) -> (p : left = right) -> c + left = c + right
plusCommutative : (left : Nat) -> (right : Nat) -> left + right = right + left
plusAssociative : (left : Nat) -> (centre : Nat) -> (right : Nat) -> left + (centre + right) = left + centre + right
plus : (n : Nat) -> (m : Nat) -> Nat

  Add two natural numbers.

  n

    the number to case-split on

  m

    the other number

multZeroRightZero : (left : Nat) -> left * 0 = 0
multZeroLeftZero : (right : Nat) -> 0 * right = 0
multRightSuccPlus : (left : Nat) -> (right : Nat) -> left * S right = left + left * right
multPowerPowerPlus : (base : Nat) -> (exp : Nat) -> (exp' : Nat) -> power base exp * power base exp' = power base (exp + exp')
multOneRightNeutral : (left : Nat) -> left * fromInteger 1 = left
multOneLeftNeutral : (right : Nat) -> fromInteger 1 * right = right
multLeftSuccPlus : (left : Nat) -> (right : Nat) -> S left * right = right + left * right
multDistributesOverPlusRight : (left : Nat) -> (centre : Nat) -> (right : Nat) -> left * (centre + right) = left * centre + left * right
multDistributesOverPlusLeft : (left : Nat) -> (centre : Nat) -> (right : Nat) -> (left + centre) * right = left * right + centre * right
multDistributesOverMinusRight : (left : Nat) -> (centre : Nat) -> (right : Nat) -> left * minus centre right = minus (left * centre) (left * right)
multDistributesOverMinusLeft : (left : Nat) -> (centre : Nat) -> (right : Nat) -> minus left centre * right = minus (left * right) (centre * right)
multCommutative : (left : Nat) -> (right : Nat) -> left * right = right * left
multAssociative : (left : Nat) -> (centre : Nat) -> (right : Nat) -> left * (centre * right) = left * centre * right
mult : Nat -> Nat -> Nat

  Multiply natural numbers

modNatNZ : Nat -> (y : Nat) -> Not (y = 0) -> Nat

  Modulus function where the divisor is not zero.

      modNatNZ 100 2 SIsNotZ

modNat : Nat -> Nat -> Nat
minusZeroRight : (left : Nat) -> minus left (fromInteger 0) = left
minusZeroN : (n : Nat) -> 0 = minus n n
minusZeroLeft : (right : Nat) -> minus (fromInteger 0) right = 0
minusSuccSucc : (left : Nat) -> (right : Nat) -> minus (S left) (S right) = minus left right
minusSuccPred : (left : Nat) -> (right : Nat) -> minus left (S right) = pred (minus left right)
minusSuccOne : (n : Nat) -> minus (S n) (fromInteger 1) = n
minusPlusZero : (n : Nat) -> (m : Nat) -> minus n (n + m) = 0
minusOneSuccN : (n : Nat) -> 1 = minus (S n) n
minusMinusMinusPlus : (left : Nat) -> (centre : Nat) -> (right : Nat) -> minus (minus left centre) right = minus left (centre + right)
minus : Nat -> Nat -> Nat

  Subtract natural numbers. If the second number is larger than the first, return 0.

minimumZeroZeroRight : (right : Nat) -> minimum (fromInteger 0) right = 0
minimumZeroZeroLeft : (left : Nat) -> minimum left (fromInteger 0) = 0
minimumSuccSucc : (left : Nat) -> (right : Nat) -> minimum (S left) (S right) = S (minimum left right)
minimumIdempotent : (n : Nat) -> minimum n n = n
minimumCommutative : (l : Nat) -> (r : Nat) -> minimum l r = minimum r l
minimumAssociative : (l : Nat) -> (c : Nat) -> (r : Nat) -> minimum l (minimum c r) = minimum (minimum l c) r
minimum : Nat -> Nat -> Nat

  Find the least of two natural numbers

maximumZeroNRight : (right : Nat) -> maximum 0 right = right
maximumZeroNLeft : (left : Nat) -> maximum left 0 = left
maximumSuccSucc : (left : Nat) -> (right : Nat) -> S (maximum left right) = maximum (S left) (S right)
maximumIdempotent : (n : Nat) -> maximum n n = n
maximumCommutative : (l : Nat) -> (r : Nat) -> maximum l r = maximum r l
maximumAssociative : (l : Nat) -> (c : Nat) -> (r : Nat) -> maximum l (maximum c r) = maximum (maximum l c) r
maximum : Nat -> Nat -> Nat

  Find the greatest of two natural numbers

lteTransitive : LTE n m -> LTE m p -> LTE n p

  `LTE` is transitive

lteSuccRight : LTE n m -> LTE n (S m)

  n < m implies n < m + 1

lteSuccLeft : LTE (S n) m -> LTE n m

  n + 1 < m implies n < m

lteRefl : LTE n n

  `LTE` is reflexive.

lteNTrue : (n : Nat) -> lte n n = True
lteAddRight : (n : Nat) -> LTE n (plus n m)
lte : Nat -> Nat -> Bool

  Boolean test than one Nat is less than or equal to another

lt : Nat -> Nat -> Bool

  Boolean test than one Nat is strictly less than another

log2NZ : (x : Nat) -> Not (x = 0) -> Nat
log2 : Nat -> Nat
lcm : Nat -> Nat -> Nat
isZero : Nat -> Bool
isSucc : Nat -> Bool
isLTE : (m : Nat) -> (n : Nat) -> Dec (LTE m n)

  A decision procedure for `LTE`

ifThenElseSuccSucc : (cond : Bool) -> (t : Nat) -> (f : Nat) -> S (ifThenElse cond (Delay t) (Delay f)) = ifThenElse cond (Delay (S t)) (Delay (S f))
ifThenElsePlusPlusRight : (cond : Bool) -> (right : Nat) -> (t : Nat) -> (f : Nat) -> ifThenElse cond (Delay t) (Delay f) + right = ifThenElse cond (Delay (t + right)) (Delay (f + right))
ifThenElsePlusPlusLeft : (cond : Bool) -> (left : Nat) -> (t : Nat) -> (f : Nat) -> left + ifThenElse cond (Delay t) (Delay f) = ifThenElse cond (Delay (left + t)) (Delay (left + f))
ifThenElseMultMultRight : (cond : Bool) -> (right : Nat) -> (t : Nat) -> (f : Nat) -> ifThenElse cond (Delay t) (Delay f) * right = ifThenElse cond (Delay (t * right)) (Delay (f * right))
ifThenElseMultMultLeft : (cond : Bool) -> (left : Nat) -> (t : Nat) -> (f : Nat) -> left * ifThenElse cond (Delay t) (Delay f) = ifThenElse cond (Delay (left * t)) (Delay (left * f))
hyper : Nat -> Nat -> Nat -> Nat
gte : Nat -> Nat -> Bool

  Boolean test than one Nat is greater than or equal to another

gt : Nat -> Nat -> Bool

  Boolean test than one Nat is strictly greater than another

gcd : (a : Nat) -> (b : Nat) -> {auto ok : NotBothZero a b} -> Nat
fromLteSucc : LTE (S m) (S n) -> LTE m n

  If two numbers are ordered, their predecessors are too

fromIntegerNat : Integer -> Nat

  Convert an Integer to a Nat, mapping negative numbers to 0

fib : Nat -> Nat

  Fibonacci numbers

fact : Nat -> Nat

  Factorial function

eqSucc : (left : Nat) -> (right : Nat) -> (p : left = right) -> S left = S right

  S preserves equality

divNatNZ : Nat -> (y : Nat) -> Not (y = 0) -> Nat

  Division where the divisor is not zero.

      divNatNZ 100 2 SIsNotZ

divNat : Nat -> Nat -> Nat
divCeilNZ : Nat -> (y : Nat) -> Not (y = fromInteger 0) -> Nat
divCeil : Nat -> Nat -> Nat
cmp : (x : Nat) -> (y : Nat) -> CmpNat x y
SIsNotZ : (S x = 0) -> Void

  The proof that no successor of a natural number can be zero.

      modNatNZ 10 3 SIsNotZ

data NotBothZero : (n : Nat) -> (m : Nat) -> Type

  Proofs that `n` or `m` is not equal to Z

  LeftIsNotZero : NotBothZero (S n) m
  RightIsNotZero : NotBothZero n (S m)
data Nat : Type

  Natural numbers: unbounded, unsigned integers which can be pattern
  matched.

  Z : Nat

    Zero

  S : Nat -> Nat

    Successor

record Multiplicative

  A wrapper for Nat that specifies the semigroup and monoid implementations that use (*)

  GetMultiplicative : Nat -> Multiplicative
  __pi_arg : (rec : Multiplicative) -> Nat
LTESuccZeroFalse : (n : Nat) -> lte (S n) 0 = False
data LTE : (n : Nat) -> (m : Nat) -> Type

  Proofs that `n` is less than or equal to `m`

  n

    the smaller number

  m

    the larger number

  LTEZero : LTE 0 right

    Zero is the smallest Nat

  LTESucc : LTE left right -> LTE (S left) (S right)

    If n <= m, then n + 1 <= m + 1

LT : Nat -> Nat -> Type

  Strict less than

GetMultiplicative : Nat -> Multiplicative
GetAdditive : Nat -> Additive
GTE : Nat -> Nat -> Type

  Greater than or equal to

GT : Nat -> Nat -> Type

  Strict greater than

data CmpNat : Nat -> Nat -> Type
  CmpLT : (y : Nat) -> CmpNat x (x + S y)
  CmpEQ : CmpNat x x
  CmpGT : (x : Nat) -> CmpNat (y + S x) y
record Additive

  A wrapper for Nat that specifies the semigroup and monoid implementations that use (+)

  GetAdditive : Nat -> Additive
  __pi_arg : (rec : Additive) -> Nat
(-) : (m : Nat) -> (n : Nat) -> {auto smaller : LTE n m} -> Nat
  Fixity
    Left associative, precedence 8