Groups 174 What's the most difficult aspect of your life as a mathematician, Diane Maclagan, an assistant professor at Rutgers, was asked. "Trying to prove theorems," she said. And the most fun? "Trying to prove theorems." Exercises 1. Prove that the external direct product of any finite number of sa group. (This exercise is referred to in this chapter.) 2. Show that Z, Z, Z, has seven subgroups of order 2 3. Let G be a group with identity e and let H be a group with iden- tity e Prove that G is isomorphic to G{e} and that H is iso morphic to (eg) H 4. Show that G H is Abelian if and only if G and H are Abelian State the general case. 5. Prove or disprove that Z Z is a cyclic group. 6. Prove, by comparing orders of elements, that Zg Z, is not iso- morphic to Z, Z 7. Prove that G, G, is isomorphic to G, G,. State the general groups 2 8 4 case. 8. Is Z,Z, isomorphic to Z2? Why? 9. Is Z,Z, isomorphic to Z? Why? 10. How many elements of order 9 does Z Z, have? (Do not do this 15 28 exercise by brute force.) 11. How many elements of order 4 does Z, Z, have? (Do not do this by examining each element.) Explain why Z Z number of elements of order 4 as does Zs00000 Z400000 ize to the case Z Z. 29 has the same General- 30 31 32 12. Give examples of four groups of order 12, no two of which are isomorphic. Give reasons why no two are isomorphic. 13. For each integer n > 1, give examples of two nonisomorphic 14. The dihedral group D, of order 2n (n 3) has a subgroup of n ro- of order n2. groups 33. tations and a subgroup of order 2. Explain why D, cannot be iso- 15. Prove that the group of complex numbers under addition is iso- 16. Suppose that G, G2 and H, H2. Prove that G, H G morphic to the external direct product of two such groups. 34. morphic to R 35. R 36. H,. State the general case. 17. If GH is cyclic, prove that G and H are 37. case. 18. In Z4 38 Z cyclic. State the genera find two subgroups of order 12. 30

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Topic Video
Question

18

Groups
174
What's the most difficult aspect of your life as a mathematician, Diane
Maclagan, an assistant professor at Rutgers, was asked. "Trying to prove
theorems," she said. And the most fun? "Trying to prove theorems."
Exercises
1. Prove that the external direct product of any finite number of
sa group. (This exercise is referred to in this chapter.)
2. Show that Z, Z, Z, has seven subgroups of order 2
3. Let G be a group with identity e and let H be a group with iden-
tity e Prove that G is isomorphic to G{e} and that H is iso
morphic to (eg) H
4. Show that G H is Abelian if and only if G and H are Abelian
State the general case.
5. Prove or disprove that Z Z is a cyclic group.
6. Prove, by comparing orders of elements, that Zg Z, is not iso-
morphic to Z, Z
7. Prove that G, G, is isomorphic to G, G,. State the general
groups
2
8
4
case.
8. Is Z,Z, isomorphic to Z2? Why?
9. Is Z,Z, isomorphic to Z? Why?
10. How many elements of order 9 does Z Z, have? (Do not do this
15
28
exercise by brute force.)
11. How many elements of order 4 does Z, Z, have? (Do not do this
by examining each element.) Explain why Z Z
number of elements of order 4 as does Zs00000 Z400000
ize to the case Z Z.
29
has the same
General-
30
31
32
12. Give examples of four groups of order 12, no two of which are
isomorphic. Give reasons why no two are isomorphic.
13. For each integer n > 1, give examples of two nonisomorphic
14. The dihedral group D, of order 2n (n 3) has a subgroup of n ro-
of order n2.
groups
33.
tations and a subgroup of order 2. Explain why D, cannot be iso-
15. Prove that the group of complex numbers under addition is iso-
16. Suppose that G, G2 and H, H2. Prove that G, H G
morphic to the external direct product of two such groups.
34.
morphic to R
35.
R
36.
H,. State the general case.
17. If GH is cyclic, prove that G and H are
37.
case.
18. In Z4
38
Z
cyclic. State the genera
find two subgroups of order 12.
30
Transcribed Image Text:Groups 174 What's the most difficult aspect of your life as a mathematician, Diane Maclagan, an assistant professor at Rutgers, was asked. "Trying to prove theorems," she said. And the most fun? "Trying to prove theorems." Exercises 1. Prove that the external direct product of any finite number of sa group. (This exercise is referred to in this chapter.) 2. Show that Z, Z, Z, has seven subgroups of order 2 3. Let G be a group with identity e and let H be a group with iden- tity e Prove that G is isomorphic to G{e} and that H is iso morphic to (eg) H 4. Show that G H is Abelian if and only if G and H are Abelian State the general case. 5. Prove or disprove that Z Z is a cyclic group. 6. Prove, by comparing orders of elements, that Zg Z, is not iso- morphic to Z, Z 7. Prove that G, G, is isomorphic to G, G,. State the general groups 2 8 4 case. 8. Is Z,Z, isomorphic to Z2? Why? 9. Is Z,Z, isomorphic to Z? Why? 10. How many elements of order 9 does Z Z, have? (Do not do this 15 28 exercise by brute force.) 11. How many elements of order 4 does Z, Z, have? (Do not do this by examining each element.) Explain why Z Z number of elements of order 4 as does Zs00000 Z400000 ize to the case Z Z. 29 has the same General- 30 31 32 12. Give examples of four groups of order 12, no two of which are isomorphic. Give reasons why no two are isomorphic. 13. For each integer n > 1, give examples of two nonisomorphic 14. The dihedral group D, of order 2n (n 3) has a subgroup of n ro- of order n2. groups 33. tations and a subgroup of order 2. Explain why D, cannot be iso- 15. Prove that the group of complex numbers under addition is iso- 16. Suppose that G, G2 and H, H2. Prove that G, H G morphic to the external direct product of two such groups. 34. morphic to R 35. R 36. H,. State the general case. 17. If GH is cyclic, prove that G and H are 37. case. 18. In Z4 38 Z cyclic. State the genera find two subgroups of order 12. 30
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 2 steps with 2 images

Blurred answer
Knowledge Booster
Discrete Probability Distributions
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, advanced-math and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,