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32 Cards in this Set
- Front
- Back
Order |
An order on S is a relation, denoted by <, with the following two properties: i) If x ϵ S and y ϵ S then one and only one of these statements is true: x < y, x = y, x > y ii) If x, y, z ϵ S, if x< y and y < z then x < z |
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Bounded Above/ Upperbound |
Consider E C S, an ordered set. E is bounded above, if there exists a B ϵ S s.t.
x <= B for all x ϵ E In this case, B is called an upperbound of E. (same for alpha lowerbound) |
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Least Upper Bound/ Supremum of E. |
Suppose E C S, an ordered set, and E is bounded above. Suppose a exists w/ these properties: i) a is an upperbound of E. ii) y < a => y is not an upper bound of E. Then a = the least upper bound of E. a = sup E (same for a = greatest lower bound of E/ inf E) |
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Least-Upper-Bound Property (LUBP) |
An ordered set S has the LUBP if
- empty set(0/) does not equal E C S, E bounded above => sup E exists in S. |
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Field |
A field is a set F w/ 2 operations (+, mult.) which satisfy the "field axioms" x, y , z ϵ F Addition: Multiplication: (A1) x + y ϵ F (M1) xy ϵ F (A2) x + y = y + x (M2) xy = yx (A3) x + (y + z) = (x+y)+z (M3) (xy)z = x(yz) (A4) 0 ϵ F s.t. 0+x=X (M4) 1ϵF s.t. 1x=x (A5) -xϵF s.t. (-x)+x=0 (M5) 1/xϵF s.t. 1/x*x=1 |
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Ordered Field |
An ordered field is a field F which also is an ordered set and x, y, z ϵF i) y < z => x +y < x+z ii) x > 0, y > 0 => xy > 0 |
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Complex conjugate z̅ |
If z = a + ib then z bar = a - ib |
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Image
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Let A and B be two sets and f be a mapping of A into B. If E C A, f(E) is defined to be the set of all elements f(x), for x ϵ E. We call f(E) the image of E under f. f(A) is the range |
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Onto |
If f(A) = B, f maps A onto B.
f ^-1(E) is the inverse image of E. |
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1-1 |
If for each x ϵ B, f^-1(y) consists of <= 1 element of A, then f is a 1-1 mapping provided that f(x1) does not equal f(x2) when x1 does not equal x2 |
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1-1 correspondence equivalent |
If there is a 1-1 mapping of A onto B, A and B can be put into 1-1 correspondence or that card(A) = card(B) or A,B are equivalent.
Card = # of elements in a set |
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Finite Infinite Countable Uncountable At most countable |
For n ϵ natural N > 0, let N(n) := {1,2,...,n} for any set A: a) A is finite if A ~ N(n) for some n ϵ natural N b) A is infinite if A is not finite c) A is countable if A ~ N(n) d) A is uncountable if A is neither finite nor countable e) A is at most countable if A is finite or count. |
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Sequence |
A sequence {Xn} C A is a function w/ domain natural N (f(n) = Xn) |
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Metric space |
Set X is a metric space if for all p, q ϵ X there is some d(p, q) ϵ Reals : a) d(p,q) > 0 if p does not equal q b) d(p,q) = d(q,p) c) d(p,q) <= d(p,r) + d(r,q) for all r ϵ X |
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Neighborhood
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A neighborhood of a point p is a set Nr(p) consisting of all points q s.t. d(p,q) < r. r is the radius of Nr(p) |
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Limit Point |
A point p is a limit point of the set E if every neighborhood of p contains a point q not equal to p s.t. q ϵ E |
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Isolated Point |
If p ϵ E and p is not a limit point of E, then p is called an isolated point of E |
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Closed Interior Open Complement |
E is closed if every limit point of E is a point of E. A point p is an interior point of E if there is some Nr(p) s.t. N C E. E is open if every point of E is an interior point of E. The complement of E(denoted E ^ c) is the set of all points p ϵ X s.t. p is not ϵ E |
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Perfect Bounded Dense |
E is perfect if E is closed and if every point of E is a limit point of E. E is bounded if there is a real number M and a point q ϵ X s.t. d(p, q) < M for all p ϵ E. E is dense in X if every point of X is a limit point of E, or a point of E( or both) |
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closure |
Let E c X, a metric space. Let E':={limit points of E}
Then the closure of E is E bar = close(E) E U E' |
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Open Cover |
Let E be a set contained in a metric space X. By open cover we mean a collection { G a} of open subsets of X s.t. E c UaGa |
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Compact |
A subset K of a metric space X is compact if every open cover contains a finite subcover. |
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Converges (diverges) |
A sequence {pn} c X, a metric space, converges if for p ϵ X all E >0 there is some N ϵ natural N :
n >= N => d(pn, p) < E
(p = lim as n->oo pn or pn -> p. If a sequence does not converge, it diverges.) |
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Subsequence Subsequential Limit |
A subsequence of {pn} is obtained from taking terms {pnk} where n1 < n2 < n3<...
If {pnk} converges, then its limit is a subsequential limit |
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Cauchy Sequence |
{pn} c X metric is a Cauchy sequence if
for all E > 0 there is some N :
n,m >= N => d(pn, pm) < E |
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Diameter of E |
empty set does not = E c X metric and let s:= {d(p,q) : p,q ϵ E}.
Diam E:= sup S |
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Cpmplete |
A metric sequence is complete if every Cauchy sequence converges |
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Upper Limit Lower Limit |
Let {sn} ϵ R and there be the set of x s.t. snk -> x for a subsequence {snk}. s* = sup E slow * = inf E s*, sLow* are called the upper and lower limits of {sn}; lim n->oo sup sn = s*, lim n->oo inf sn =slow* |
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Infinite Series/Series |
The summation from n = 1 to oo of An = S
if Sn = the summation from k = 1 to n of Ak is the partial series. |
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Power Series (coefficients |
Fix a sequence {Cn} c Complex numbers The summation from n = 0 to oo of Cnz^n, z ϵ Complex is a power series
(Cn are the coefficients of the series) |
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Product of the summation of An and Bn |
Given summation An, summation Bn, then
Cn = summation from k = 0 to n of AkBn-k, n ϵ N0 is the product of the two summations. |
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X, Y metric spaces, f: Ec X -> y, p limit point of E
f(x) -> q as x -> p or lim x->p f(x) = q if... |
there is q ϵ Y s.t.
for all E>0 there is some delta> 0 : 0< dX(x,p) < delta |