Permutation Definition and 276 Threads

  1. Matejxx1

    How Can Students Be Arranged into Groups with Set Sizes?

    Homework Statement There are 30 students in a class. In how many ways can we arrange them if : a)we must have three group, group one must have 5 students , group two 10 students and group three 15 students. answer=\frac{30!}{5!*10!*15!} b)we must have three group and all must have 10 students...
  2. Matejxx1

    How Many 5-Digit Numbers from 4, 5, 6, 8, 9 are Divisible by 8?

    Homework Statement From the numbers 4,5,6,8,9 we make 5 digits numbers (each number can be used only once). h)How many of these numbers are divisible by 8? The correct answer is 20 Homework Equations a number is divisible by 8 if the last 3 digits are divisible by 8 If the hundreds digit is...
  3. P

    Algorithm for creating unique groups of elements

    Homework Statement so for a side task I'm supposed to assign people to groups for an icebreaker in python, can anyone give me links to theories that I could read up on or give me suggestion X number of people at my company signed up for a dinner roulette as a way to meet new people. Everyone...
  4. R

    Solving using permutation and combination

    Homework Statement From 5 consonants and 4 vowels, how many words can be formed consisting of 3 consonants and 2 vowels The book solved it using combination C(5,3) * C(4,2) * 5! = 7200 i.e I understand the 1st two term give the unique 5 words that can be formed with 5 consonants and 4 vowels...
  5. R

    Cards and envelopes permutation problem

    Homework Statement Six cards and six envelopes are numbered 1,2,3,4,5,6 and cards are to be placed in envelopes so that each envelope contains exactly one card and no card is placed in the envelope bearing the same number and moreover the card numbered 1 is always placed in envelope numbered 2...
  6. B

    Proof using Permutation Symbols

    Homework Statement Proove that... (AxB)x(CxD)=(A.BxD)C-(A.BxC)D=(A.CxD)B-(B.CxD)A using Permutation Symbols Homework EquationsThe Attempt at a Solution I am confused about what to do after the third line from 'vela's response' (Post #2 from the reference link below). Reference...
  7. M

    How Many Unique 7-Digit Numbers Can Be Formed Using Specific Repeated Digits?

    How many 7-digit numbers can be formed from the digits 1, 1, 2, 2, 4, 4 and 5 if repetition is not allowed. If one of these numbers is chosen at random, find the probability that it is(a) greater than 4,000,000(b) even number and greater than 4,000,000 Question b is so confusing . Help me
  8. I

    No cycles in permutation N how to calculate sgn(N^2)?

    N is a 2 x n matrix: N = 1 2 3 4 ... n-1 n n n-1 ... 4 3 2 1 then N^2 = 1 2 3 4 ... n-1 n 1 2 3 4 ... n-1 nYou COULD use the theorem: sgn(N^2) = sgn(N)sgn(N) however, I am asked to find sgn(N^2) by the traditional method: sgn(N^2) = (-1)^([L1 - 1] + [L2 - 1]...) where L represents the...
  9. I

    How Do You Calculate the Square of a Permutation Matrix?

    say i have the matrix (4,2,5,6,3,1) and on top I have (1,2,3,4,5,6) i.e. a 2x6 permutation matrix. Let's call it sigma. how would I calculate (sigma)^2? I can break it down into cycles: sigma = <1,4,6>compose<3,5> thanks.
  10. K

    MHB Properties of permutation of a set

    I am doing some self study of groups and can solve problem #3 but not Problem #4. Problem 3. Let A be a finite set, and B a subset of A. Let G be the subset of S_A consisting of all of the permutations f of A such that f(x) is in B for every x in B. Prove that G is a subgroup of S_A. Problem...
  11. F

    MHB Permutation and Combination Homework Help

    Hey guys, there's these questions in my hm that's really tough for me and i basically have no clue on how to do it. Any help is greatly appreciated 1.a) Give the numbers 1,1,2,3,4,5,5,6,7, If five numbers are randomly selected without replacement, how many different numbers can be formed if...
  12. R

    How many ways can 6 cards be chosen from a deck to have all suits present?

    Homework Statement In how many ways can one choose 6 cards from a normal deck of cards so as to have all suits present?Homework EquationsThe Attempt at a Solution 4 different cards can be chosen in 13*13*13*13 ways. Now we have to choose 2 remaining cards from 48 cards. This can be done in...
  13. S

    Find Prashad's Course Choice Combinations - Explained

    Homework Statement On his university application, Prashad must list his course choices in order of preference. He must choose four of the six courses available in his major discipline and three of the four courses offered in related subjects. In how many ways can Prashad list his course...
  14. R

    Einstein notation and the permutation symbol

    Homework Statement This is my first exposure to Einstein notation and I'm not sure if I'm understanding it entirely. Also I added this class after my instructor had already lectured about the topic and largely had to teach myself, so I ask for your patience in advance... The question is...
  15. M

    Parity of Permutations: Understanding Even and Odd Cycles

    I'm asked to show that a permutation is even if and only if the number of cycles of even length is even. (And also the odd case) I'm having trouble getting started on this proof because the only definitions of parity of a permutation I can find are essentially this theorem. And obviously I...
  16. J

    Proving Permutation Inverses: (1 2 3) = (4 5 6)

    Homework Statement Prove that there is a permutation sigma, such that sigma * (1 2 3) * sigma inverse= (4 5 6). Homework Equations The Attempt at a Solution I know that since the order of the two cycles is the same there must be a sigma such that the two permutations are equal but I...
  17. J

    Determining Missing Images in an Even Permutation

    Homework Statement Hi, I have been MIA lately due to work, but I am back with questions, and eager to learn! I am self studying, and so I have inconsistencies in my learning which I hope to iron out. Suppose you are told that the permutation ( 1 2 3 4 5 6 7 8 9 3 1 2 X Y 7 8 9 6) In S9...
  18. S

    Problems on permutation and combination

    Homework Statement a) How many different initials can someone have if a person has at least two, but no more than five, initials? You may assume that each initial is one of the 26 uppercase letters of English, and that letters can be repeated. b) When attempting to name his son, Jor El...
  19. I

    How many ways can a security code be formed with restrictions?

    Homework Statement A security code is formed by using three alphabet and four digits chosen from alphabet {a,b,c,d,e} and digits {1,2,3,4,5,6}. All digits and alphabets can only be used once. Find the number of different ways the security code can be formed if (a) there is no restriction...
  20. KodRoute

    How do I determine the sign of this permutation

    Homework Statement Find the sign of the permutation --> Picture here: http://tinypic.com/view.php?pic=2q8rkso&s=5 No other given data. Homework Equations ε(σ) = (-1)^m(σ). If i < j and σ(i) > σ(j) then there's an inversion. Where ε(σ) denotes the sign of the permutation and m(σ) the number of...
  21. N

    MHB More Permutation and Combination questions

    Reviewing for my final exam can anyone please help access these problems? a) How many ways can 11 football players stand in a circular huddle? I put 11P11 b) 12 identical laptops are in the inventory of a dealer, and 2 have hidden defects. If 5 computers to be shipped are selected at random...
  22. K

    MHB Permutation representation argument validity

    Hello, I would like to check if the work I have done for this problem is valid and accurate. Any input would be appreciated. Thank you. **Problem statement:** Let $G$ be a group of order 150. Let $H$ be a subgroup of $G$ of order 25. Consider the action of $G$ on $G/H$ by left...
  23. K

    MHB Surjectivity for permutation representation of a group action

    I am having trouble proving that my function is surjective. Here is the problem statement: Problem statement: Let T be the tetrahedral rotation group. Use a suitable action of T on some set, and the permutation representation of this action, to show that T is isomorphic to a subgroup of $S_4$...
  24. J

    How Many Unique 5 White and 5 Black Bead Necklaces Can Be Made?

    Homework Statement How many necklace with 5 white beads and 5 black beads can be constructed? Homework Equations Circular Permutation problem The Attempt at a Solution] I did 10!/5!5!=252 but from there I didn't get anywhere. I know this includes repeats from rotational...
  25. Raerin

    MHB Exploring the Possibilities: Solving an 8-Digit Even Number Permutation Question

    It's a permutation question, so I don't know where else to post this. How many eight digit even numbers are possible with the digits 7 5 4 5 7 5 0 7? Please explain step by step.
  26. P

    How Is the Permutation Approximation Proven for Large N?

    How can I prove that, for N\gg n \frac{N!}{(N-n)!}\approx N^{n} I've tried doing \frac{N!}{(N-n)!}=\exp\left(\ln\frac{N!}{(N-n)!}\right)=\exp\left(\ln N!-\ln\left(N-n\right)!\right) \underset{stirling}{\approx}\exp\left(N\ln N-N-\left(N-n\right)\ln\left(N-n\right)+N-n\right)...
  27. V

    Recognizing even or odd permutation easily?

    Hello folks, I'm not even sure if this is the place to put this but with some luck it might be. I just have a general question about permutations. I understand the concept of even and odd permutations of a set of numbers, what I am hoping for is an easy way to figure out if (given a...
  28. B

    Does every permutation of group generators imply an automorphism?

    I couldn't find the words to summarize my question perfectly in the title so I will clarify my question here. Say we have a group G in which every element can be written in the form g_1^{e_1} g_2^{e_2}...g_n^{e_n}, 0 ≤ e_i < |g_i| . Suppose that there exists a different set g_1', g_2', ...
  29. B

    A permutation and combination problem

    Homework Statement There are 2n points on a circle, we want to connect each two of them to make a pattern of connection in the way that there is no cross between the lines of connection, and all the lines have to be inside the circle and on the plane of the circle. Question: How many different...
  30. B

    Proving Permutation Identity: Ʃ(n choose k)(m-n choose n-k) = (m choose n)

    [b]1. Prove the following identity: Ʃ(n choose k)(m-n choose n-k) = (m choose n) from k = 0 to k = n I've tried induction, and just played around with a few properties of permutations, but nothing seems to satisfy the proof, any ideas?
  31. K

    How Many Ways Can a Postman Deliver 4 Wrong Letters to 4 Houses?

    Homework Statement A notorious postman delivered 4 letters to four houses in such a way that no house will get the correct letter...in how many ways he delivered the letter ? Please explain it Homework Equations I think this is permutation question...using fundamental law of counting...
  32. J

    MHB Permutation of Letters: 10 Choose 4 with 4 Letter Gap between P and S

    Total no. of permutation of the words $\bf{PERMUTATIONS}$ in which there are exactly $4$ letters between $P$ and $S$, is My TRY:: If we fixed $P$ and $S$, Then there are $10$ letters $\bf{ERMUTATIONS}$ out of $10$, we have to select $4$ letters of $4$ gap b/w $P$ and $S$ and then arrange in...
  33. S

    Can the 1296 permutation ever be extended?

    Hi everyone, I have a problem I'm trying to solve. If anybody can help it would be greatly appreciated. (PS: My understanding of maths is so poor I don't even understand the meaning of half the forum titles so please excuse me if I've posted in the wrong section..!) All the possible 2...
  34. N

    Decompose the permutation into the direct sum of irreducible reps.

    Homework Statement Note: I need help with part (c). Consider the representation P: S_3 \rightarrow GL_3 where P_{\sigma} is the permutation matrix associated to \sigma. a) Determine the character \chi_P : S_3 \rightarrow \mathbb{C} b) Find all the irreducible representations of S_3. c)...
  35. D

    Solving Permutation Matrices: Show PT(I+P)=(I+P)T

    Homework Statement Supposing P is a permutation matrix, I have to show that PT(I+P) = (I+P)T. Is there any general form of a permutation matrix I should use here as permutation matrices of a dimension can come in various forms. Homework Equations The Attempt at a Solution I did...
  36. C

    How to do cyclic permutation on interatomic matrix elements?

    For example, how to obtain E_(yz,xz)(l,m,n) from E_(xy,xz)(l,m,n)?
  37. S

    Permutation and Combination problem

    Homework Statement The total number of ways in which 5 balls of different colours can be distributed among 3 persons so that each person gets at least one ball is ... Homework Equations The Attempt at a Solution I began by finding the number of ways of distributing 5 balls among...
  38. B

    Combinatorial question: permutation, binomial coefficient

    How many numbers of 6 digits which have exatctly the digit 1 (2 times), digit 2 (2 times), without zero, are there? The book post this solution: \frac{6!}{2!2!}*\binom{7}{2} + \frac{6!}{2!2!2!}*7= 4410, but I'm trying to find an explanation for this result.
  39. I

    MHB Does the permutation group S_8 contain elements of order 14?

    Does the permutation group $S_8$ contain elements of order $14$?My answer: If $\sigma =\alpha \beta$ where $\alpha$ and $\beta$ are disjoint cycles, then $|\sigma|=lcm(|\alpha|, |\beta|)$ . Therefore the only possible disjoint cycle decompositions for a permutation $\sigma \in S_8$ with...
  40. E

    How Many Quadratic Equations Can Be Formed With Real Roots?

    Homework Statement If three different number are taken from the set {0, 1, 3, 5, 7} to be used as the coefficient of a standard quadratic equation, how many such quadratic equations can be formed? How many of these have real roots?Homework Equations The Attempt at a Solution Part a: "How many...
  41. Z

    Permutation question with a dial

    Homework Statement So, you have a dial with 12 numbers (1 through 12), and you're wondering how many ways can you connect an number to another. So its therefor asking how many lines can you make with 1 - 12 in a circle. Homework Equations The Attempt at a Solution I got the...
  42. L

    What Is a Permutation and Can You Provide an Example?

    what is the permutation? and like what example? anyone knows?
  43. B

    Is My Approach to Solving This Permutation Problem Correct?

    Homework Statement http://i49.tinypic.com/wmmhbl.png Homework Equations The Attempt at a Solution my answers : Q1:(a) (i) 8! (ii) 4!*5! Q1:(b) 7P3*5P2 Q2: 4320 ways Q3: 12!*3! Are my answers correct?
  44. B

    How Many Ways Can You Solve This Permutation Problem?

    Homework Statement http://i49.tinypic.com/2hoeghs.png Homework Equations The Attempt at a Solution (i) 144 ways (ii) 2!*4!*3! (iii) 12*5! these are my answers
  45. E

    Finding Correct Combination/Permutation Rule for Statistics Project

    This is NOT homework. This is a personal project I am working on. First and foremost, THANK YOU in advance for helping me with my statistics project that I have been unable to solve on my own or through the help of my statistics book and google. I am working on an excel spreadsheet for use...
  46. V

    How Many Six-Digit Numbers Have Three Even and Three Odd Digits?

    Homework Statement How many different six-digit numbers are there whose three digits are even and three digits are odd? Homework Equations No equations are required.We only need the principles of counting. The Attempt at a Solution I tried to split into 4 cases: case I:there is...
  47. P

    Find the Total Number of Arrangements for Six Mobsters in Line

    Question: Six mobsters have arrived at the theater for the premiere of the film “Goodbuddies.” One of the mobsters, Frankie, is an informer, and he's afraid that another member of his crew, Joey, is on to him. Frankie, wanting to keep Joey in his sights, insists upon standing behind Joey in...
  48. T

    Difficulty with permutation and combination

    Right I am having an issue with the proof to permutation, I really can see the n-r-1 I think the confusion stems because it is in the general term, which throws me a bit, if possible could someone maybe write it in numbers and the underneath write in the general term if not too much trouble. The...
  49. B

    MHB Permutations of Comics, Novels, and Magazines Without Restrictions

    There are three separate bundles of reading material comprising of 4 comics, 2 novels and 3 magazines. They are placed together to form one pile. In how many ways can this be done if there are no restrictions on where the individual items are to be placed? I say 9! = 362880 Determine the...
  50. F

    Abstract Algebra Order of Permutation

    Homework Statement See image. Homework Equations The Attempt at a Solution I am finding the orders of permutations. I know that you first find the orbits or cycles I don't know the difference (but I should). This is what my professor said: If you have (1345)(897)...
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