
Please post any and all homework or other textbookstyle problems in one of the Homework & Coursework Questions...

Feb2313 09:25 AM
micromass

1 
32,454 
mathworld defines the paradox like this:"Even though real arithmetic is uncountable, it possesses a countable...

Oct1703 05:54 PM
Hurkyl

1 
2,372 
i found in this paper the term in the title:
http://arxiv.org/abs/math.GR/9305201
what can you tell me about them?...

Apr1204 02:19 PM
matt grime

1 
2,584 
in this page ive encountered this topic (it's a topic from combinatorics, so it's relevant to discrete maths with sets...

Jul205 03:23 AM
MathematicalPhysicist

3 
1,648 
prove that \epsilon_0 is an \epsilon number and that it's the smallest number.
\epsilon_0=\lim_{n<\omega}\phi(n)...

Aug3006 03:18 AM
matt grime

1 
1,540 
i searched at amazon for books, and find some books about this topic, and i wonder what does this topic cover?
in one...

Apr1906 03:11 PM
Hurkyl

3 
1,874 
1)let P={p1,p2....} be the set of all prime numbers for every n natural, present n as a representation of its prime...

Apr2706 02:20 PM
HallsofIvy

33 
2,698 
i have a few question, that i hope they will answered.
1) let w={0,1...,n,..}={0}UN, and let f:wxw>w such that the...

Jun1506 02:21 PM
CrankFan

18 
1,645 
i need to prove that if x is the first of sub(\phi;a,\psi) then there exists 1<=i<=n and there exist firsts \phi' of...

Jul2306 08:55 AM
MathematicalPhysicist

1 
1,989 
i read that there are some logicians who do not use the axiom of choice in their axioms systems. i wonder what is the...

Aug3106 02:16 AM
MathematicalPhysicist

2 
1,382 
what are the current open problems in logic? in model theory, proof theory and philosophical logic? and what are the...

Oct906 03:14 AM
matt grime

4 
2,074 
i think that i read that the compactness theorem in logic has a similar theorem in topology.
i wanted to inquire, are...

Nov1006 07:24 AM
HallsofIvy

3 
2,142 
how do i show that Y^(XU{x})=(Y^X)x(Y^{x}) where X and Y are finite sets, and {x} is a singleton.
obvisouly i need to...

Nov1806 06:43 AM
matt grime

4 
1,092 
i have a function f:R>R where f is monotone increasing, i need to show that the set of discontinuous points of f is...

Dec706 12:42 PM
HallsofIvy

5 
4,604 
i have a function f:A>B, im also given that B<=null aleph, and for every b in B, f^1({b})<=null aleph, i need to...

Dec1106 12:33 PM
MathematicalPhysicist

2 
1,650 
1. i need to show that the set A={x in Q0<=x<=1}
Q is the rationals set.
can be covered by open intervals I_k (k is...

Dec2806 11:59 AM
EnumaElish

34 
3,983 
i need to find the cardinality of the set of all concave polygons.
i know that each npolygon is characterized by...

Dec3006 08:01 AM
MathematicalPhysicist

12 
2,188 
i need to find the cardinality of set of continuous functions f:R>R.
well i know that this cardinality is samaller...

Jan107 03:34 AM
AKG

14 
6,799 
i need to prove that there are c sqequences of rational numbers.
basically, i need to show that Q^N=c.
here, are a...

Jan407 07:13 AM
HallsofIvy

3 
1,382 
i need to show that there exists a class of sets A which is a subset of P(Q) such that it satisfies:
1) A=c (c is...

Jan807 11:47 AM
MathematicalPhysicist

14 
2,562 
i need to prove that X is an infinite set iff for every function f:X>X there exists a proper nonempty subset A of X...

Feb1507 04:25 PM
AKG

6 
1,847 
i need to prove the next statement:
let D be infinite class of infinite subsets of natural numbers that satisfies the...

Feb1307 07:19 AM
ecurbian

5 
1,478 
1)axiom of choice: prove that for every set X and for every f:X>X there exists g:X>X such that fogof=f.
2)zorn's...

Feb1307 08:52 AM
MathematicalPhysicist

0 
1,066 
let R be a reflexive and symmetric relation on a set X. let's define a relation S on X. by (x,y) in S iff there exists...

Feb1407 10:07 AM
MathematicalPhysicist

0 
1,931 
suppose our language contains one unary syombol function.
we are given the next 5 models:
A=<Z,x+1> B=<Z,x1>...

Mar3107 09:24 AM
MathematicalPhysicist

2 
1,412 
let r>1 which term in (x1+...+xk)^rk has the greatest coefficient?
well i have this equation: ...

Apr907 05:29 AM
MathematicalPhysicist

1 
3,287 
let a\in R and Q>=3 where Q\in Z, i need to prove that in the set {a,2a,...,(Q1)a} there exists a number which its...

Apr3007 02:01 PM
AKG

9 
2,149 
my question is as follows:
how many words with n letters, you can construct with A,T,G,C such that ACT and TTT will...

Jun1507 04:45 AM
MathematicalPhysicist

0 
1,257 
question in model theory.
let L={P_nn \in N}
every P_n is an unary predicate. let's define a theory that says...

Jun1707 10:50 AM
MathematicalPhysicist

0 
1,129 
I need to find:
1. let n be a natural number compute the number of permutations s:{1,...,3n}>{1,...,3n} on 3n terms...

Jul207 02:05 AM
MathematicalPhysicist

8 
1,391 
how many words of length k can you create from {1,...,k} such that 1 appears even number of times?
well, for k=0 we...

Jul207 06:05 AM
MathematicalPhysicist

5 
1,992 
My problem is as follows:
Prove that the set of Godel numbers of provable formulas (P_f) is recursive iff the set of...

Dec1807 12:03 PM
MathematicalPhysicist

0 
1,985 
I'm not sure I understnad what is a marginal distribution, but i need to show that if F1,F2 are one dimensional...

Feb908 03:41 PM
EnumaElish

1 
2,413 
Let X,Y~U(0,1) independent (which means that they are distributed uniformly on ). find the distribution of U=XY....

Feb2908 08:03 PM
quadraphonics

2 
4,959 
I have a graph G with n vertices, with connectivity \kappa(G)=k i.e its k connected, I need to show that
...

Dec110 07:08 PM
ych22

4 
1,304 
I need help with question number 8, I thought I had it right the proof of the lower bound, but now I see my solution...

Dec810 02:01 AM
MathematicalPhysicist

0 
754 
I am given a graph G with 1000 vertices and 250,001 edges and I need to show there are two triangles in it with common...

Jan1611 03:20 PM
MathematicalPhysicist

1 
806 
I have the next two signals:
X(t) and G(t) and a random process Y(t)=G(t)X(t) where X(t) and G(t) are wide sense...

Apr513 11:12 PM
MathematicalPhysicist

3 
529 
Hi, I have the next RV:
$$\underline{W}=\frac{\underline{X}}{\frac{\underline{X}}{\sqrt{n}}}$$
where $$X_i...

May2013 03:01 PM
mathman

1 
516 
Hey everyone,
I have a question regarding combinations and poker! Could someone explain to me why the number of...

Apr2112 09:57 AM
Stephen Tashi

3 
1,436 
What are the current capabilities of modern Theorem Provers? I know about logic/undecidability/complexity theory so go...

Feb514 11:39 AM
Hornbein

4 
401 