Shared Flashcard Set

Details

Real Analysis
Real Analysis
61
Mathematics
Undergraduate 3
06/11/2016

Additional Mathematics Flashcards

 


 

Cards

Term

Least Upper Bound Property

 

An ordered set S is said to have the least-upper-bound property if:

 

for E < S, E not empty, and E bounded above, then

Definition
sup E exists in S.
Term

Suppose S is an ordered set with the LUB property, B<S, B not empty, and B bounded below. Then

 

1) α = sup L ____

 

2) α = 

 

3) In particular, inf B ____

Definition

1) exists in S 

 

2) inf B

 

3) exists in S

Term

An ordered field is a field F which is also an ordered set, such that:

 

1) x+y < x+z if ___

 

2) xy > 0 if ___

Definition

1) x,y,z ∈ F and y < z


2) x ∈ F, y ∈ F, x > 0, and y > 0

Term

Archimedian Property


If x ∈ , y ∈ R, and x > 0, then

Definition

there exists a positive integer n such that nx > y

Term

Q is dense in R 

 

 If x ∈ , y ∈ R, and x < y, then

Definition
there exists p ∈ Q such that x < p <y.
Term
Given x, y, z in R,|x - z|___
Definition
|x - z| ≤ |x - y| + |y - z|| 
Term
A point p is a limit/accumulation point of the set E if ___
Definition
every neighborhood of/open subset of E containing p contains a point q ≠p ∈ E.
Term
If p ∈ E and p is not a limit/accumulation point of E, then p is called an
Definition
isolated point of E.
Term
E is closed if 
Definition
every limit/accumulation point of E is contained in E.
Term
A point p of E is an interior point of E if
Definition
there is a neighborhood N of p such that N <  E.
Term
E is open if
Definition
every point of E is an interior point of E.
Term
The complement of E (denoted Ec) is 
Definition
the set of all points p ∈ metric space X such that p ∉ E.
Term
E is perfect if 
Definition
E is closed and if every point of E is a limit point of E.
Term
E is bounded if
Definition
there is a real number M and a point q ∈ metric space X such that d(p,q) < M for all p ∈ E.
Term
E is dense in metric space X if
Definition
every point of X is a limit point of E, or a point of E (or both).
Term
Every neighborhood is
Definition
an open set.
Term
If p is a limit point of a set E, thene
Definition
every neighborhood of p contains infinitely many points of E.
Term
A finite set has no
Definition
limit points.
Term
Let {Ea} be a (finite or infinite) collection of sets Ea. Then (a Ea)c =
Definition
a (Eac).
Term
A set E is open iff its
Definition
complement is closed.
Term

1) If X is a metric space with E < X, and if E' denotes the set of all limit points of E in X, then the closure of E is___


2) Ē is ___


3) E = Ē iff


4) Ē < F for every

Definition

1) the set Ē ∪ E'.


2) closed.


3) E is closed.


4) closed set F < X such that E < F.

Term
Let E be a nonempty set of real numbers which is bounded above. Let y = sup E. Then 
Definition
 Ē. Hence y ∈ E if E is closed.
Term
An open cover of a set E in a metric space X is a
Definition
collections {Ga} of open subsets of X such that E < a Ga.
Term
A subset K of a metric space X is said to be compact ife
Definition
every open cover of K contains a finite subcover.
Term
Compact subsets of metric spaces are
Definition
closed.
Term
Closed subsets of compact sets are
Definition
compact.
Term
If F is closed and K is compact, then F ∩ K is
Definition
compact.
Term
If E is an infinite subset of a compact set K, then E
Definition
has a limit point in K.
Term

Heine-Borel

 

For a set E in Rk, the following properties are equivalent:

 

1) E is closed and

 

2) E is

 

3) Every infinite subset of E has

Definition

1) bounded.

 

2) compact

 

3) a limit point in E.

Term

Weierstrass

 

Every bounded infinite subset of Rk has

Definition
a limit point in Rk.
Term
Let P be a nonempty perfect set in Rk. Then P is
Definition
uncountable.
Term

1) Two subsets A and B of a metric space X are said to be separated if 

 

2) A set E < X is said to be connected if E is *not*

Definition

1) both A ∩ cl(B) and cl(A) ∩ B are empty; i.e., if no point of A lies in the closure B and no point of B lies in the closure of A.


2) a union of two nonempty separated sets.

Term
A subset E of the real line R is connected iff
Definition
for all x ∈ E, y ∈ E, and x < z < y, then z ∈ E.
Term

1) A sequence {fn} in a metric space X is said to converge if

 

2) In this case, limn→∞ =

Definition

1) there exists a point p ∈ X such that for every ε > 0 there exists an integer N such that n ≥ N implies d(fn, fm) < ε.


2) p



Term

Let {fn} be a sequence in a metric space X.

 

a) {fn} converges to p ∈ X iff 


b) If p ∈ X, p'  X, and if {fn} converges to p and p', then


c) If {fn} converges, then 


d) If E < X and if p is a limit point of E, then

Definition

a) every neighborhood of p contains fn for all but finitely many n.

 

b) p'= p.

 

c) {fn} is bounded.

 

d) there is a sequence {fn} in E such that p = limn→∞ fn.

Term

1) Given a sequence {fn}, consider  sequence {nk} of positive integers, such that n1 < n2 < ... Then the sequence {fni} is called a


2) If {fni} converges, its limit is called a

Definition

1) subsequence of {fn}.

 

2) subsequential limit of {fn}.

Term

a) If {fn} is a sequence in a compact metric space X, then

 

b) Every bounded sequence in Rk contains

Definition

a) some subsequence of {fn} converges to a point of X.

 

b) a convergent subsequence.

Term
The subsequential limits of a sequence {fn} in a metric space X form
Definition
a closed subset of X.
Term

A sequence {fn} in a metric space X is said to be a Cauchy sequence if

Definition
for every ε > 0 there exists an integer N such that d(fn,fm) < ε if n ≥ N and m ≥ N.
Term
Let E be a nonempty subset of a metric space X, and let S be the set of all real numbers of the form d(p,q) with p  E and q ∈ E. The sup of S is called
Definition
the diameter of E.
Term

1) Given a set E in a metric space X, diam E =

 

2) If K is a sequence of compact sets in X such that Kn > Kn+1 (n=1,2,3,...), and if limn→∞ Kn = 0, then

Definition

1) diam cl(E).

 

2) ∩1 Kn consists of exactly one point.

Term

a) In any metric space X, every convergent sequence is a 

 

b) If X is a compact metric space, and if {fn} is a Cauchy sequence in X, then

 

c) In Rk, every Cauchy sequence

Definition

a) Cauchy sequence.

 

b) {fn} converges to some point in X.

 

c) converges.

Term
A metric space in which every Cauchy sequence converges is said to be
Definition
complete.
Term
Suppose {sn} is monotonic. Then {sn} converges iff
Definition
it is bounded.
Term

a) If p > 0, then limn→∞ 1/np

 

b) If p > 0, then limn→∞ n√p =

 

c) limn→∞ n√n =

 

d) If p > 0 and a is real, then limn→∞ na/(1+p)n =

 

e) If |x| < 1, then limn→∞ xn =

Definition

a) 0

 

b) 1

 

c) 1

 

d) 0

 

e) 0

 

 

 

Term
Σan converges iff for every ε > 0, there exists an integer N such that 
Definition
mk=n ak| ≤ ε if m ≥ n ≥ N.
Term
If Σan converges, then limn→∞ an =
Definition
Term
A series of non-negative terms converges iff
Definition
its partial sums form a bounded sequence.
Term

a) If |an| ≤ cn for n ≥ N0, where N0 is some fixed integer, and if Σcn converges, then 

 

b) If an ≥ dn ≥ 0 for n ≥ N0, and if Σdn diverges, then

Definition

a) Σan converges.

 

b) Σan diverges.

Term

a) If |an| ≤ cn for n ≥ N0, where N0 is some fixed integer, and if Σcn converges, then 

 

b) If an ≥ dn ≥ 0 for n ≥ N0, and if Σdn diverges, then

Definition

a) Σan converges.

 

b) Σan diverges.

Term

1. If 0≤x<1, then Σn=0 xn =


2. If x≥1, then the series

Definition

1. 1/(1-x)

 

2. diverges.

Term
Suppose a1 ≥ a2 ≥ ... ≥ 0. Then the series Σn=0 an converges iff the series
Definition
Σk=0 2ka2k = a1 + a2 + 4a4 + 8a8 converges.
Term

1. Σ 1/np converges if

 

2. and diverges if

Definition

1. p > 1.

 

2. p ≤ 1.

Term

1. If p > 1, then Σn=2 1/(nlogn)p___


2. If p ≤ 1, then

Definition

1. converges

 

2. the series diverges

Term
e =
Definition
Σn=0  1/n!
Term
limn→∞  (1 +1/n)n =
Definition
e
Term

Root Test

 

Given Σan , define L = limn→∞ |an|1/n

 

a) if L < 1, then Σan ___

 

b) if L > 1, then Σan ___

 

c) if L = 1, then___

Definition

a) converges

 

b) diverges

 

c) the test gives no information.

Term

Ratio Test

 

Given the series Σan, define  [image]. Σan


a) Converges if 


b) Diverges if 

Definition

a) L < 1

 

b) |(an+1)/an| ≥ 1 for all n ≥ n0, where n0 is some fixed integer, or L > 1

Term

Given the power series Σn=0 cn(x-a)n about a, define  α= limn→∞ sup n√|cn|, R = 1/α, 


a) If α = 0, R = 

b) If α = +, R =

c) Σn=0 cn(x-a)n converges if

d) Σn=0 cn(x-a)n diverges if 

Definition

a) +

b) 0

c) |x - a| < R

d)  |x - a| > R

Term

Given two sequences {an} and {bn}, define

AnΣnk=0  ak if n ≥ 0; and define A-1 = 0. Then, if 0 ≤ p ≤ q, we have Σqn=p anbn =

Definition
Σq-1n=p An(bn - bn+1) + Aqbq - Ap-1bp
Term

Σanbn converges if

 

a) the partial sums An of Σan ___

 

b) b0 ___

 

c) limn→∞ bn = ___

Definition

a) form a bounded sequence

 

b) ≥ b1 ≥ b2 ≥ ...

 

c) 0

Supporting users have an ad free experience!