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Statement List for Metamath Proof Explorer - 6201-6300 - Page 63 of 108
TypeLabelDescription
Statement
 
Theorempeano2uz2 6201 Second Peano postulate for upper integers.
|- ((A e. ZZ /\ B e. {x e. ZZ | A <_ x}) -> (B + 1) e. {x e. ZZ | A <_ x})
 
Theoremdfuz 6202 An expression for the upper integers that start at N that is analogous to df-n 5925 for natural numbers. Warning: The HTML proof page is 1/2 megabyte in size.
|- N e. ZZ   =>   |- {z e. ZZ | N <_ z} = |^|{x | (N e. x /\ A.y e. x (y + 1) e. x)}
 
Theorempeano5uz 6203 Peano's inductive postulate for upper integers.
|- A e. V   &   |- N e. ZZ   =>   |- ((N e. A /\ A.x e. A (x + 1) e. A) -> {k e. ZZ | N <_ k} (_ A)
 
Theorempeano5uzt 6204 Peano's inductive postulate for upper integers.
|- A e. V   =>   |- (N e. ZZ -> ((N e. A /\ A.x e. A (x + 1) e. A) -> {k e. ZZ | N <_ k} (_ A))
 
Theoremuzind 6205 Induction on the upper integers that start at M. The first four hypotheses give us the substitution instances we need; the last two are the basis and the induction hypothesis.
|- (j = M -> (ph <-> ps))   &   |- (j = k -> (ph <-> ch))   &   |- (j = (k + 1) -> (ph <-> th))   &   |- (j = N -> (ph <-> ta))   &   |- (M e. ZZ -> ps)   &   |- ((M e. ZZ /\ k e. ZZ /\ M <_ k) -> (ch -> th))   =>   |- ((M e. ZZ /\ N e. ZZ /\ M <_ N) -> ta)
 
Theoremuzind2 6206 Induction on the upper integers that start after an integer M. The first four hypotheses give us the substitution instances we need; the last two are the basis and the induction hypothesis.
|- (j = (M + 1) -> (ph <-> ps))   &   |- (j = k -> (ph <-> ch))   &   |- (j = (k + 1) -> (ph <-> th))   &   |- (j = N -> (ph <-> ta))   &   |- (M e. ZZ -> ps)   &   |- ((M e. ZZ /\ k e. ZZ /\ M < k) -> (ch -> th))   =>   |- ((M e. ZZ /\ N e. ZZ /\ M < N) -> ta)
 
Theoremuzind3 6207 Induction on the upper integers that start at an integer M. The first four hypotheses give us the substitution instances we need, and the last two are the basis and the induction hypothesis.
|- (j = M -> (ph <-> ps))   &   |- (j = m -> (ph <-> ch))   &   |- (j = (m + 1) -> (ph <-> th))   &   |- (j = N -> (ph <-> ta))   &   |- (M e. ZZ -> ps)   &   |- ((M e. ZZ /\ m e. {k e. ZZ | M <_ k}) -> (ch -> th))   =>   |- ((M e. ZZ /\ N e. {k e. ZZ | M <_ k}) -> ta)
 
TheoremuzindOLD 6208 Induction on the upper integers that start at an integer B. The first four hypotheses give us the substitution instances we need; the last two are the basis and the induction hypothesis.

Warning: The HTML proof page is 3/4 megabyte in size. An attempt to shorten it is on my to-do list.

|- (x = B -> (ph <-> ps))   &   |- (x = y -> (ph <-> ch))   &   |- (x = (y + 1) -> (ph <-> th))   &   |- (x = A -> (ph <-> ta))   &   |- ps   &   |- (((y e. ZZ /\ B e. ZZ) /\ B <_ y) -> (ch -> th))   =>   |- (((A e. ZZ /\ B e. ZZ) /\ B <_ A) -> ta)
 
Theoremuzind3OLD 6209 Induction on the set of upper integers that starts at B. The first four hypotheses give us the substitution instances we need, and the last two are the basis and the induction hypothesis.
|- (x = B -> (ph <-> ps))   &   |- (x = y -> (ph <-> ch))   &   |- (x = (y + 1) -> (ph <-> th))   &   |- (x = A -> (ph <-> ta))   &   |- ps   &   |- ((B e. ZZ /\ y e. {z e. ZZ | B <_ z}) -> (ch -> th))   =>   |- ((B e. ZZ /\ A e. {z e. ZZ | B <_ z}) -> ta)
 
Theoremuzwo4OLD 6210 Well-ordering principle: any non-empty subset of the upper integers has a least element.
|- ((B e. ZZ /\ (A (_ {z e. ZZ | B <_ z} /\ A =/= (/))) -> E.x e. A A.y e. A x <_ y)
 
Theoremuzwo5OLD 6211 Well-ordering principle: any non-empty subset of upper integers has a unique least element.
|- ((B e. ZZ /\ (A (_ {z e. ZZ | B <_ z} /\ A =/= (/))) -> E!x e. A A.y e. A x <_ y)
 
Theoremnn0ind 6212 Principle of Mathematical Induction (inference schema) on nonnegative integers. The first four hypotheses give us the substitution instances we need; the last two are the basis and the induction hypothesis.
|- (x = 0 -> (ph <-> ps))   &   |- (x = y -> (ph <-> ch))   &   |- (x = (y + 1) -> (ph <-> th))   &   |- (x = A -> (ph <-> ta))   &   |- ps   &   |- (y e. NN0 -> (ch -> th))   =>   |- (A e. NN0 -> ta)
 
Theoremnn0indALT 6213 Principle of Mathematical Induction (inference schema) on nonnegative integers. The first four hypotheses give us the substitution instances we need; the last two are the basis and the induction hypothesis.
|- (y e. NN0 -> (ch -> th))   &   |- ps   &   |- (x = 0 -> (ph <-> ps))   &   |- (x = y -> (ph <-> ch))   &   |- (x = (y + 1) -> (ph <-> th))   &   |- (x = A -> (ph <-> ta))   =>   |- (A e. NN0 -> ta)
 
Theoremnn0ind-raph 6214 Principle of Mathematical Induction (inference schema) on nonnegative integers. The first four hypotheses give us the substitution instances we need; the last two are the basis and the induction hypothesis. (Contributed by Raph Levien, 10-Apr-2004. Raph says: "This seems a bit painful. I wonder if an explicit substitution version would be easier.")
|- (x = 0 -> (ph <-> ps))   &   |- (x = y -> (ph <-> ch))   &   |- (x = (y + 1) -> (ph <-> th))   &   |- (x = A -> (ph <-> ta))   &   |- ps   &   |- (y e. NN0 -> (ch -> th))   =>   |- (A e. NN0 -> ta)
 
Theorembtwnz 6215 Any real number can be sandwiched between two integers. Exercise 2 of [Apostol] p. 28.
|- (A e. RR -> (E.x e. ZZ x < A /\ E.y e. ZZ A < y))
 
Well-ordering principle for bounded-below sets of integers
 
Theoremuzwo3lem1 6216 Lemma for uzwo3 6218 and zmin 6219.
 
Theoremuzwo3lem2 6217 Lemma for uzwo3 6218.
 
Theoremuzwo3 6218 Well-ordering principle: any non-empty subset of upper integers has a unique least element. This generalization of uzwo2 6457 allows the lower bound B to be any real number. See also nnwo 6458 and nnwos 6460.
|- ((B e. RR /\ (A (_ {z e. ZZ | B <_ z} /\ A =/= (/))) -> E!x e. A A.y e. A x <_ y)
 
Theoremzmin 6219 There is a unique smallest integer greater than or equal to a given real number.
|- (A e. RR -> E!x e. ZZ (A <_ x /\ A.y e. ZZ (A <_ y -> x <_ y)))
 
Theoremzmax 6220 There is a unique largest integer less than or equal to a given real number.
|- (A e. RR -> E!x e. ZZ (x <_ A /\ A.y e. ZZ (y <_ A -> y <_ x)))
 
Theoremzbtwnre 6221 There is a unique integer between a real number and the number plus one. Exercise 5 of [Apostol] p. 28.
|- (A e. RR -> E!x e. ZZ (A <_ x /\ x < (A + 1)))
 
Theoremrebtwnz 6222 There is a unique greatest integer less than or equal to a real number. Exercise 4 of [Apostol] p. 28.
|- (A e. RR -> E!x e. ZZ (x <_ A /\ A < (x + 1)))
 
The floor (greatest integer) function
 
Syntaxcfl 6223 Extend class notation with floor (greatest integer) function.
class |_
 
Definitiondf-fl 6224 Define the floor (greatest integer) function. See flvalt 6225 for its value, flleltt 6228 for its basic property, and flclt 6226 for its closure.

The term "floor" was coined by Ken Iverson. He also invented a mathematical notation for floor, consisting of an L-shaped left bracket and its reflection as a right bracket. In APL, the left-bracket alone is used, and we borrow this idea. (Thanks to Paul Chapman for this information.)

|- |_ = {<.x, y>. | (x e. RR /\ y = U.{z e. ZZ | (z <_ x /\ x < (z + 1))})}
 
Theoremflvalt 6225 Value of the floor (greatest integer) function. The floor of A is the (unique) integer less than or equal to A whose successor is strictly greater than A.
|- (A e. RR -> (|_` A) = U.{x e. ZZ | (x <_ A /\ A < (x + 1))})
 
Theoremflclt 6226 The floor (greatest integer) function is an integer (closure law).
|- (A e. RR -> (|_` A) e. ZZ)
 
Theoremflreclt 6227 The floor (greatest integer) function is real.
|- (A e. RR -> (|_` A) e. RR)
 
Theoremflleltt 6228 A basic property of the floor (greatest integer) function.
|- (A e. RR -> ((|_` A) <_ A /\ A < ((|_` A) + 1)))
 
Theoremfllet 6229 A basic property of the floor (greatest integer) function.
|- (A e. RR -> (|_` A) <_ A)
 
Theoremflltp1t 6230 A basic property of the floor (greatest integer) function.
|- (A e. RR -> A < ((|_` A) + 1))
 
Theoremfraclt1t 6231 The fractional part of a real number is less than one.
|- (A e. RR -> (A - (|_` A)) < 1)
 
Theoremfracge0t 6232 The fractional part of a real number is nonnegative.
|- (A e. RR -> 0 <_ (A - (|_` A)))
 
Theoremflget 6233 The floor function value is the greatest integer less than or equal to its argument.
|- ((A e. RR /\ B e. ZZ) -> (B <_ A <-> B <_ (|_` A)))
 
Theoremflltt 6234 The floor function value is less than the next integer.
|- ((A e. RR /\ B e. ZZ) -> (A < B <-> (|_`
 A) < B))
 
Theoremflidt 6235 An integer is its own floor.
|- (A e. ZZ -> (|_` A) = A)
 
Theoremflidmt 6236 The floor function is idempotent.
|- (A e. RR -> (|_` (|_` A)) = (|_` A))
 
Theoremflwordit 6237 Ordering relationship for the greatest integer function.
|- ((A e. RR /\ B e. RR /\ A <_ B) -> (|_` A) <_ (|_` B))
 
Theoremflval2t 6238 An alternate way to define the floor (greatest integer) function.
|- (A e. RR -> (|_` A) = U.{x e. ZZ | (x <_ A /\ A.y e. ZZ (y <_ A -> y <_ x))})
 
Theoremflval3t 6239 An alternate way to define the floor (greatest integer) function, as the supremum of all integers less than or equal to its argument.
|- (A e. RR -> (|_` A) = sup({x e. ZZ | x <_ A}, RR, < ))
 
Theoremflbit 6240 A condition equivalent to floor.
|- ((A e. RR /\ B e. ZZ) -> ((|_` A) = B <-> (B