1. T

    operation count for Gaussian Elimination

    I know additional line of finding a new pivot and swapping doesn't change the operation count , of gaussian elimination, can someone please explain why this is the case?
  2. S

    When am I supposed to add numbers or just count them in this Venn question

    Should I add them when the question is about Union and I should only count the numbers when the question is a bout intersection.
  3. M

    Poincaré Disc Model - what is it, exactly? What projected shapes do, and don't, count

    I am trying to get a handle on what is and is not the Poincaré disc model. I think I see over on wiki that it's the projection of a given wibbly shape, through a disc to a point. As in this image, shamelessly linked from aforementioned Wiki: So there's my disc, in grey, at the bottom, and on...
  4. A

    Where do the Numbers we count with come from?

    How do mathamaticians experience what we call numbers? Do they describe all the numbers we use, as a part of infinity, or do all numbers mathamaticians use come from 1?
  5. L

    Count the next five numbers in hexadecimal, starting with the following:

    a. 3AB7 b. 6FD c. B9E My answers are: a. 3AB7, 3AB8, 3AB9, 3ABA, 3ABB, 3ABC b. 6FD, 6FE, 6FF, 700, 701, 702 c. B9E, B9F, BA0, BA1, BA2, BA3 Are these correct?
  6. S

    is this count as a linear order relation?

    say A is: A=\left \{ \left \{ a \right \}, \left \{ a,b \right \}\right \} and R being: R=\left \{( \left \{ a \right \},\left \{ a \right \}), (\left \{ a,b \right \},\left \{ a,b \right \}),(\left \{ a \right \},\left \{ a,b \right \}) \right \} and let's say the relation is "subset of"...
  7. A

    Multiple regression for count data or a proportion

    Hi all I was wondering if some one could give me advise on the appropriate multivariate statistical test to use and if they have or know of a suitable website with a worked example using R to carry out the test (including test diagnostics). The outcome variable is data (count or a...
  8. P

    Calculate significance of difference in count numbers between populations

    probability of count numbers between populations difference Hi I'm comparing genomic distribution counts of two subsets of a dataset that were composed using different selection criteria. Both subsets contain x values corresponding to the genomic startpositions of probes used on an array to...
  9. M

    Using product buy count data to determine popularity.

    Hi All I'm not sure if this classifies as an "advanced" question. It's challenging for me and I studied maths in university (although admittedly it wasn't my strongest point). Heh... (Thinking) Here's the problem: I'm in the process of regularly scraping a range of online deal pages...
  10. M

    How to count tiles of same color?

    I want to count the max tiles of the same color in picture as below, for this picture, the right result should be as below, how can I get a algorithm to calculate this? pink=6, green=5, blue=2, yellow=1
  11. M

    What does 3^n count?

    I am asked to prove, combinatorially: 2 \cdot 3^0+2 \cdot 3^1+2 \cdot 3^2+\ldots+ 2 \cdot 3^{n-1}=3^n-1 Are they kidding about this? It took me less than half a minute to prove it by factoring out the 2 and using the geometric series. The book has an example which says...
  12. H

    Do Repeated Elements in a Set Count

    How many elements are there in {1,1,1}?
  13. S

    Count numbers greater than a given number

    Hi ! I have a matrix and i want to count numbers greater than a given number. What is the easiest way of doing this task? A couple of related functions would be very useful. I will check the syntax myself. Many thanks. simonwei
  14. B

    Borda Count Method

    The Mathematics Department is holding an election for department chair. Each member ranks the candidates from first to third. The preference table below shows the results of the ballots with candidates Clark (C), Jones (J), and Smith (S). I had to attach the table in Wordpad because the format...
  15. C

    What does it mean to "count" bijections

    Count the bijections from A to B, given that |A|=|B|= n. homework hint: No proof required. Count the bijections from {1,2} to {1,2}, then count the bijections from {1,2,3} to {1,2,3}, etc. When you are confident you know the formula for the number of bijections from {1,2,...,n} to {1,2,...n}...
  16. P

    renewcommand \section* or adding number count

    I have two master files (a,b) that use the same content file (c). when I compile with file a I wish the section and subsection titles to have the characteristics of \section (i.e. section numbering) yet when I compile with b that it would have the characteristics of \section* I thought I could...
  17. P

    triangular count

    How many equilateral triangles are there in an eight-fold triangular grid. I was able to determine the number of 1x1, 2x2, 3x3, 4x4, 5x5, 6x6, 7x7, and 8x8 size triangles to be 64, 43, 27, 16, 10, 3, 1 respectively and the total number of triangles to be 170. I am having a hard time though...
  18. Biologist617

    Advice needed for bacterial population count

    I'm a biotech PhD student currently researching a rice disease throughout Asia known as rice blight. Unfortunately my knowledge of statistics is quite weak, but I would really like some advice from anybody who can help. I apologise for the lengthy explanation. Background: Xanthomonas oryzae is...
  19. A

    minimum cycle count on a non-plannar graph

    Hi, Does anybody knows a way to count algorithmically the number of cycles in a non-plannar graph, keeping a record of their lenghts? I am an architect (so not quite an mathematical expert). In my PhD I am using a technique known as 'space syntax' to represent and analyze spatial systems as...
  20. R

    matlab - image analysis - count objects

    hello everyone i have an image which contains 1's and 0's. i want to identify them somehow and then write them to an array. I figure out that it must have something to do with edge detection and bwmorph operations, but i am lost. Have you got any idea, how to do this? it 's the first time i 'm...