## Search found 27 matches

Wed Oct 10, 2012 10:43 am UTC
Forum: Mathematics
Topic: What is wrong with this inference?
Replies: 2
Views: 1749

### What is wrong with this inference?

What is wrong with this inference? Are there any mistakes? (See the attachment).
inference.pdf
(41.58 KiB) Downloaded 183 times

I hope we could discuss it more.
Regards.
Wed Mar 07, 2012 10:50 am UTC
Forum: Computer Science
Topic: Iterative Form for Strassen Algorithm
Replies: 3
Views: 2809

### Iterative Form for Strassen Algorithm

As we all already know, the Strassen algorithm for n by n matrix multiplication is written in recursive form. It has been proven (see: http://stackoverflow.com/questions/931762/can-every-recursion-be-converted-into-iteration for the detail) that any recursive algorithm can be transformed into its it...
Wed Mar 07, 2012 10:40 am UTC
Forum: Mathematics
Topic: Getting my undergrad in math. How about you?
Replies: 51
Views: 8485

### Re: Getting my undergrad in math. How about you?

Age: 24 Education: B.S. in Math, M.S. in Computer Science What am I doing: Currently I am working as teaching assistant for freshmen and sophomores, for Linear Algebra and Discrete Math. I am also doing some research in formal method area. Hopefully my paper will be accepted this year. My Plan: Purs...
Fri Jan 27, 2012 8:02 am UTC
Forum: Mathematics
Topic: Open Problems in Logic?
Replies: 4
Views: 1688

### Re: Open Problems in Logic?

Perhaps this site could help you

http://garden.irmacs.sfu.ca/?q=container/area.
Thu Apr 14, 2011 5:39 am UTC
Forum: Mathematics
Topic: Boolean Logic vs Fuzzy Logic
Replies: 1
Views: 3766

### Boolean Logic vs Fuzzy Logic

I currently have a question about fuzzy logic algebra. My professor said that any fuzzy logic algebra could never satisfy all properties which are satisfied in boolean algebra. Is is true? The properties in boolean logic algebra are: 1. idempotent: P AND P = P and P OR P = P. 2. commutative: P AND Q...
Tue Nov 30, 2010 4:03 am UTC
Forum: Computer Science
Topic: Shortest maximum contiguous sub sequence problem
Replies: 5
Views: 4769

### Re: Shortest maximum contiguous sub sequence problem

Understand that your post looks like a homework assignment. And reading a random algorithm by some random stranger won't help you understand how to come up with algorithms. Well, I'll have an exam in algorithm analysis and design class this December. My professor give a bunch of exercise, one of th...
Tue Nov 30, 2010 3:49 am UTC
Forum: Computer Science
Topic: Interesting Problem in Graph Algorithm
Replies: 18
Views: 3890

### Re: Interesting Problem in Graph Algorithm

I found a hamiltonian path in this graph, the path is G-C-D-E-O-A-B-F. If we can find hamiltonian path in this graph, then the total distance to visit all cities will be minimum, am I correct? I found that the total distance of this path is 58. That's way I thought a hamiltonian path will solve this...
Mon Nov 29, 2010 4:36 pm UTC
Forum: Mathematics
Topic: How hard is college level mathematics?
Replies: 36
Views: 9752

### Re: How hard is college level mathematics?

If you like challenges, then probably you should try some undergrad math contest. There are so many undergrad math contest, if you live in North America, you can try your luck at Putnam Math Contest. If you live somewhere else, you still can compete in IMC (International Math Competition) or ISOM (I...
Mon Nov 29, 2010 4:28 pm UTC
Forum: Computer Science
Topic: Interesting Problem in Graph Algorithm
Replies: 18
Views: 3890

### Re: Interesting Problem in Graph Algorithm

The naive dynamic tree solution is n^2 2^n time-space complexity (use a bit-tree for "has visited" plus pair of "starting at" and "ending at"). That is better than n!, but only marginally. Where can I find the pseudo-code for the naive dynamic tree solution? Do you hav...
Mon Nov 29, 2010 4:26 pm UTC
Forum: Computer Science
Topic: Shortest maximum contiguous sub sequence problem
Replies: 5
Views: 4769

### Re: Shortest maximum contiguous sub sequence problem

summax:=0 for i=1 to n for j=i to n sum:=sum+a[j] if summax<sum then summax:=sum min_index:=i max_index:=j O.K, so how's the algorithm for this problem which runs in O(n log n)? Do you have any idea? :?
Mon Nov 29, 2010 1:27 pm UTC
Forum: Computer Science
Topic: Interesting Problem in Graph Algorithm
Replies: 18
Views: 3890

### Re: Interesting Problem in Graph Algorithm

I'd try to do some dynamic programming in this problem. One of my professor said that what if the problem is modified as follow: General Dimas doesn't have to begin his conquest from city O, but he still have to conquer all cities. Then the modified problem is how to find Hamiltonian Path on the gra...
Mon Nov 29, 2010 1:15 pm UTC
Forum: Computer Science
Topic: Shortest maximum contiguous sub sequence problem
Replies: 5
Views: 4769

### Shortest maximum contiguous sub sequence problem

Hi, I'm currently in Algorithm Design and Analysis class and currently doing some exercise in divide and conquer algorithm. One of the interesting problem is the shortest maximum contiguous sub sequence problem. The problem is stated as below: Consider a finite sequence of a real numbers a,a,a...
Mon Nov 29, 2010 6:32 am UTC
Forum: Computer Science
Topic: Pseudo-code for Coppersmith-Winograd Algorithm
Replies: 5
Views: 7365

### Re: Pseudo-code for Coppersmith-Winograd Algorithm

Did you try the papers linked on the wikipedia article? I've read the original paper about the algorithm cited by Wikipedia, however http://www.cs.umd.edu/~gasarch/ramsey/matrixmult.pdf didn't explain the pseudo-code explicitly. I also read http://www.siam.org/pdf/news/174.pdf and http://arxiv.org/...
Sat Nov 27, 2010 4:22 pm UTC
Forum: Computer Science
Topic: Pseudo-code for Coppersmith-Winograd Algorithm
Replies: 5
Views: 7365

### Re: Pseudo-code for Coppersmith-Winograd Algorithm

Well, I just curious how is the Coppersmith-Winograd algorithm looked. I'm planning to run a simulation of to multiply two 100 by 100 matrices and compare at least three algorithm to the process, i.e. the naive method, Strassen, and Coppersmith-Winograd.
Sat Nov 27, 2010 12:39 pm UTC
Forum: Computer Science
Topic: Pseudo-code for Coppersmith-Winograd Algorithm
Replies: 5
Views: 7365

### Pseudo-code for Coppersmith-Winograd Algorithm

Hi, I'm currently in Algorithm Design and Analysis class and doing some exercise about matrix multiplication algorithm. I read in the wikipedia that the fastest algorithm known to solve the multiplication of two square matrices is Coppersmith-Winograd algorithm. I've searched in google for the pseud...
Fri Nov 26, 2010 6:49 am UTC
Forum: Computer Science
Topic: Interesting Problem in Graph Algorithm
Replies: 18
Views: 3890

### Re: Interesting Problem in Graph Algorithm

So is there any effective algorithm to solve this problem? Or perhaps, to determine the shortest path of the conquest, General Dimas have to try with brute force search? Fri Nov 26, 2010 3:53 am UTC
Forum: Computer Science
Topic: Interesting Problem in Graph Algorithm
Replies: 18
Views: 3890

### Re: Interesting Problem in Graph Algorithm

Well, I think that we can't use Dijkstra algorithm on it, since General Dimas have to attack all cities, and we can't use TSP since the General doesn't have to get back to O and he can revisit the city he has visited (attacked).
Fri Nov 26, 2010 3:36 am UTC
Forum: Computer Science
Topic: Interesting Problem in Graph Algorithm
Replies: 18
Views: 3890

### Re: Interesting Problem in Graph Algorithm

Last night I found that General Dimas can conquer all 7 cities with total distance 67. The sequence is: O-A-B-F-B-C-D-E-D-C-G Is this the shortest distance of the conquest? I have a conjecture: in this problem, General Dimas should attack city G last, since city G can only accessed through C and the...
Thu Nov 25, 2010 9:03 am UTC
Forum: Computer Science
Topic: Interesting Problem in Graph Algorithm
Replies: 18
Views: 3890

### Re: Interesting Problem in Graph Algorithm

The distance matrix is symmetric, then I do not need to fill all of its entries.
Thu Nov 25, 2010 9:01 am UTC
Forum: Computer Science
Topic: Interesting Problem in Graph Algorithm
Replies: 18
Views: 3890

### Interesting Problem in Graph Algorithm

I'm recently doing an exercise in graph algorithm, at first it seemed to be easy, but then I realize that I did something wrong in my analysis. So here is my problem. Supposes that General Dimas wants to conquer 7 city, namely the city are A, B, C, D, E, F, G. The rule of the conquest are defined as...
Wed Feb 18, 2009 8:38 am UTC
Forum: Mathematics
Topic: Oh Linear Algebra, how I curse thee
Replies: 54
Views: 5615

### Re: Oh Linear Algebra, how I curse thee

Please help me. It's urgent. Thank you. Why is it urgent? HE MUST SOLVE THE PROOF IN 19 HOURS, 47 MINUTES OR THE PRESIDENT WILL BE ASSASSINATED! DEAR GOD MAN HAVE SOME COMPASSION! Please help me...No one will hurt if someone can answer my problem, even Kim Jong Il, the evil bad (poor) guy of N.Kore...
Tue Feb 17, 2009 8:42 am UTC
Forum: Mathematics
Topic: Oh Linear Algebra, how I curse thee
Replies: 54
Views: 5615

### Re: Oh Linear Algebra, how I curse thee

I have a question about linear algebra, please help me. Suppose C is a submodule of Z_m^n ( Z_m is a ring of integer modulo m) and C^\perp its orthogonal (that is <x,c>=0 (Euclidean inner product modulo m) for all c in C, x in C^\perp ). Find a homomorphism f:Z_m^n \rightarrow Z_m^n which satisfy Im...
Wed Jan 21, 2009 6:17 am UTC
Forum: Mathematics
Topic: Modules
Replies: 13
Views: 2300

### Re: Modules

I have a question about "modular independent vectors" definitions: Suppose \mathbb{Z}^n_m be a module of (ring) integer modulo m. Vectors v_1,v_2,...,v_k in \mathbb{Z}^n_m said to be modular independent if a_1v_1+a_2v_2+...+a_kv_k= 0 implies a_1,a_2,...,a_k are non-units in \mathbb{Z}_m pr...
Thu Jan 15, 2009 2:50 am UTC
Forum: Mathematics
Topic: Trouble using Beamer
Replies: 3
Views: 1638

### Re: Trouble using Beamer

Hello I have several difficulties using beamer. I use Scientific Workplace (SWP) to make beamer slide, I use a non-English language and I have certain LaTeX typeset objects to be translated (e.g Fact= fait , proof= preuve ,etc) . Please help me. Did anyone have beamer tutorial for SWP in PDF? :( :(
Fri Nov 28, 2008 6:29 am UTC
Forum: Mathematics
Topic: Modules
Replies: 13
Views: 2300

### Re: Modules

Is it true that for every vector spaces V (of field F): dim(C)+dim(C^\perp)=dim(V) my linear algebra lectures said: dim(C)+dim(C^\perp)=dim(V) since V=C \oplus C^\perp and C \cap C^\perp=\{0\} . Therefore dim (C \cap C^\perp)=0 , and dim(V&...
Thu Nov 27, 2008 8:41 am UTC
Forum: Mathematics
Topic: Modules
Replies: 13
Views: 2300

### Re: Modules

I already tried to solve it, since C is submodule of \mathbb{Z}^n_m then C is additive subgroup of \mathbb{Z}^n_m , therefore |C| divides |\mathbb{Z}^n_m|= m^n , thus k|C|=m^n , for some k \in \mathbb{N} . Note that C' is also submodule of \mathbb{Z}^n_m , then p|C'|=\mathbb{Z}^n_m , for some p ...
Thu Nov 27, 2008 4:28 am UTC
Forum: Mathematics
Topic: Modules
Replies: 13
Views: 2300

### Modules

Hello anyone, can you help me please...This is important (it's not too hard tough, but I still confuse) Let C be submodule of Z^n_m and C' its orthogonal (that is <x,c>=0 for all c in C, x in C'). Prove that |C| |C'| = m^n . Note: Z_m is a ring of integer 0,1,...,n-1 please help me...it's urgent... ...

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