Difference between revisions of "Special linear group:SL(2,3)"
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* It is the {{special linear group}} of [[member of family::special linear group of degree two|degree two]] over a field of three elements. In other words, it is the group of <math>2 \times 2</math> matrices with determinant <math>1</math> over the field of three elements. | * It is the {{special linear group}} of [[member of family::special linear group of degree two|degree two]] over a field of three elements. In other words, it is the group of <math>2 \times 2</math> matrices with determinant <math>1</math> over the field of three elements. | ||
* It is the [[double cover of alternating group]] <math>2 \cdot A_4</math>, i.e., it is the double cover of [[alternating group:A4]]. | * It is the [[double cover of alternating group]] <math>2 \cdot A_4</math>, i.e., it is the double cover of [[alternating group:A4]]. | ||
− | * It is a [[binary von Dyck group]] with the parameters <math>(3,3 | + | * It is a [[binary von Dyck group]] with the parameters <math>(2,3,3)</math>, i.e., it has the presentation: |
<math>\langle a,b,c \mid a^3 = b^3 = c^2 = abc \rangle</math>. | <math>\langle a,b,c \mid a^3 = b^3 = c^2 = abc \rangle</math>. | ||
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! Function !! Value !! Similar groups !! Explanation | ! Function !! Value !! Similar groups !! Explanation | ||
|- | |- | ||
− | | {{arithmetic function value order|24}} || As <math>SL(2,q)</math>, <math>q = 3</math>: <math>q^3 - q = 3^3 - 3 = 24</math><br>As <math>2 \cdot A_n, n = 4</math>: <math>n! = 4! = 24</matH><br>As [[binary von Dyck group]] with parameters <math>(p,q,r) = (3,3 | + | | {{arithmetic function value order|24}} || As <math>SL(2,q)</math>, <math>q = 3</math>: <math>q^3 - q = 3^3 - 3 = 24</math><br>As <math>2 \cdot A_n, n = 4</math>: <math>n! = 4! = 24</matH><br>As [[binary von Dyck group]] with parameters <math>(p,q,r) = (2,3,3)</math>: <math>\frac{4}{1/p + 1/q + 1/r - 1} = \frac{4}{1/2 + 1/3 + 1/3 - 1} = \frac{4}{1/6} = 24</math> |
|- | |- | ||
| {{arithmetic function value given order|exponent of a group|12|24}} || Elements of order <math>2,3,4,6</math>. | | {{arithmetic function value given order|exponent of a group|12|24}} || Elements of order <math>2,3,4,6</math>. | ||
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|} | |} | ||
− | ===Arithmetic functions of | + | ===Arithmetic functions of an element-counting nature=== |
{| class="sortable" border="1" | {| class="sortable" border="1" | ||
− | ! Function !! Value !! Explanation | + | ! Function !! Value !! Similar groups !! Explanation for function value |
|- | |- | ||
− | | | + | | {{arithmetic function value given order|number of conjugacy classes|7|24}} || As <matH>SL(2,q), q = 3</math> (odd): <math>q + 4 = 3 + 4 = 7</math><br>As [[binary von Dyck group]] with parameters <math>(p,q,r) = (2,3,3)</math>: <math>p + q + r - 1 = 2 + 3 + 3 - 1 = 7</math><br>As <math>2 \cdot A_n, n = 4</math>: (number of unordered integer partitions of <math>n</math>) + 3(number of partitions of <math>n</math> into distinct odd parts) - (number of partitions of <math>n</math> with a positive even number of even parts and with at least one repeated part) <math>= 5 + 3(1) - 1 = 7</math><br>See [[element structure of special linear group:SL(2,3)]] |
|- | |- | ||
− | | | + | | {{arithmetic function value given order|number of equivalence classes under rational conjugacy|5|24}} || See [[element structure of special linear group:SL(2,3)]] |
|- | |- | ||
− | | | + | | {{arithmetic function value given order|number of conjugacy classes of rational elements|3|24}} || See [[element structure of special linear group:SL(2,3)]] |
+ | |} | ||
+ | |||
+ | ===Arithmetic functions of a subgroup-counting nature=== | ||
+ | |||
+ | {| class="sortable" border="1" | ||
+ | ! Function !! Value !! Similar groups !! Explanation for function value | ||
+ | |- | ||
+ | | {{arithmetic function value given order|number of subgroups|15|24}} || | ||
+ | |- | ||
+ | | {{arithmetic function value given order|number of conjugacy classes of subgroups|7|24}} || | ||
|} | |} | ||
==Group properties== | ==Group properties== | ||
− | {| class=" | + | ===Important properties=== |
− | !Property !! Satisfied !! Explanation | + | |
+ | {| class="sortable" border="1" | ||
+ | !Property !! Satisfied? !! Explanation | ||
|- | |- | ||
|[[Dissatisfies property::Abelian group]] || No || | |[[Dissatisfies property::Abelian group]] || No || | ||
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|- | |- | ||
|[[Satisfies property::Solvable group]] || Yes || Length three, commutator subgroup is the quaternion group, next commutator subgroup is center. | |[[Satisfies property::Solvable group]] || Yes || Length three, commutator subgroup is the quaternion group, next commutator subgroup is center. | ||
+ | |} | ||
+ | |||
+ | ===Other properties=== | ||
+ | |||
+ | {| class="sortable" border="1" | ||
+ | !Property !! Satisfied? !! Explanation | ||
|- | |- | ||
|[[Dissatisfies property::T-group]] || No || | |[[Dissatisfies property::T-group]] || No || | ||
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|- | |- | ||
|[[Dissatisfies property::Group having subgroups of all orders dividing the group order]] || No || | |[[Dissatisfies property::Group having subgroups of all orders dividing the group order]] || No || | ||
+ | |- | ||
+ | |[[Satisfies property::Schur-trivial group]] || Yes || {{fillin}} | ||
|} | |} | ||
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{{further|[[element structure of special linear group:SL(2,3)]]}} | {{further|[[element structure of special linear group:SL(2,3)]]}} | ||
+ | ===Summary=== | ||
+ | {{#lst:element structure of special linear group:SL(2,3)|summary}} | ||
{{#lst:element structure of special linear group:SL(2,3)|conjugacy and automorphism class structure}} | {{#lst:element structure of special linear group:SL(2,3)|conjugacy and automorphism class structure}} | ||
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The automorphism group of <math>SL(2,3)</math> is isomorphic to the [[symmetric group:S4|symmetric group of degree four]]. The [[inner automorphism group]], which is the quotient of <math>SL(2,3)</math> by its center, and is also the [[projective special linear group]] <math>PSL(2,3)</math>, is isomorphic to the [[alternating group:A4|alternating group of degree four]]. | The automorphism group of <math>SL(2,3)</math> is isomorphic to the [[symmetric group:S4|symmetric group of degree four]]. The [[inner automorphism group]], which is the quotient of <math>SL(2,3)</math> by its center, and is also the [[projective special linear group]] <math>PSL(2,3)</math>, is isomorphic to the [[alternating group:A4|alternating group of degree four]]. | ||
− | To see how the outer automorphisms act, we can view <math>SL(2,3)</math> as a subgroup of index two in <math>GL(2,3)</math>, the [[general linear group:GL(2,3)|general linear group of order two over the field of three elements]]. | + | To see how the outer automorphisms act, we can view <math>SL(2,3)</math> as a subgroup of index two in <math>GL(2,3)</math>, the [[general linear group:GL(2,3)|general linear group of order two over the field of three elements]]. The inner automorphism group, which is <math>PGL(2,3)</math>, is isomorphic to the symmetric group of degree four. Since <math>SL(2,3)</math> is a normal subgroup, and since its center equals the center of <math>GL(2,3)</math>, the automorphisms of <math>GL(2,3)</math> all restrict to automorphisms of <math>SL(2,3)</math>. <math>SL(2,3)</math> has no other automorphisms. |
==Subgroups== | ==Subgroups== | ||
{{further|[[Subgroup structure of special linear group:SL(2,3)]]}} | {{further|[[Subgroup structure of special linear group:SL(2,3)]]}} | ||
− | |||
{{#lst:subgroup structure of special linear group:SL(2,3)|summary}} | {{#lst:subgroup structure of special linear group:SL(2,3)|summary}} | ||
+ | ===Subgroup-defining functions=== | ||
+ | {{#lst:subgroup structure of special linear group:SL(2,3)|sdf summary}} | ||
==Supergroups== | ==Supergroups== | ||
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The special linear group <math>SL(2,3)</math> is a subgroup of the general linear group <math>GL(2,3)</math>. It is also a subgroup of <math>SL(2,q)</math> for any prime power <math>q \ge 3</math> (note that <math>q</math> need not be a power of <math>3</math>). {{proofat|[[SL(2,3) is a subgroup of any special linear group]], [[Dickson's theorem]]}} | The special linear group <math>SL(2,3)</math> is a subgroup of the general linear group <math>GL(2,3)</math>. It is also a subgroup of <math>SL(2,q)</math> for any prime power <math>q \ge 3</math> (note that <math>q</math> need not be a power of <math>3</math>). {{proofat|[[SL(2,3) is a subgroup of any special linear group]], [[Dickson's theorem]]}} | ||
− | == | + | ==GAP implementation== |
− | {| | + | {{GAP ID|24|3}} |
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− | |} | ||
− | == | + | ===Other descriptions=== |
− | {| class=" | + | {| class="sortable" border="1" |
− | ! | + | ! Description !! Functions used |
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|- | |- | ||
− | | | + | | <tt>SL(2,3)</tt> <br>or <br><tt>SpecialLinearGroup(2,3)</tt> || [[GAP:SL|SL]] |
|- | |- | ||
− | | | + | | <tt>SchurCover(AlternatingGroup(4))</tt> || [[GAP:SchurCover|SchurCover]], [[GAP:AlternatingGroup|AlternatingGroup]] |
|} | |} | ||
− | + | ===Description by presentation=== | |
− | = | ||
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− | === | ||
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<pre>F := FreeGroup(3); | <pre>F := FreeGroup(3); | ||
G := F/[F.1^3*F.2^(-3), F.2^3*F.3^(-2), F.1^3*(F.1*F.2*F.3)^(-1)];</pre> | G := F/[F.1^3*F.2^(-3), F.2^3*F.3^(-2), F.1^3*(F.1*F.2*F.3)^(-1)];</pre> |
Latest revision as of 03:52, 3 May 2015
This article is about a particular group, i.e., a group unique upto isomorphism. View specific information (such as linear representation theory, subgroup structure) about this group
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Contents
Definition
The special linear group is defined in the following equivalent ways:
- It is the special linear group of degree two over a field of three elements. In other words, it is the group of matrices with determinant over the field of three elements.
- It is the double cover of alternating group , i.e., it is the double cover of alternating group:A4.
- It is a binary von Dyck group with the parameters , i.e., it has the presentation:
.
It is a group of order .
Arithmetic functions
Arithmetic functions of an element-counting nature
Arithmetic functions of a subgroup-counting nature
Function | Value | Similar groups | Explanation for function value |
---|---|---|---|
number of subgroups | 15 | groups with same order and number of subgroups | groups with same number of subgroups | |
number of conjugacy classes of subgroups | 7 | groups with same order and number of conjugacy classes of subgroups | groups with same number of conjugacy classes of subgroups |
Group properties
Important properties
Property | Satisfied? | Explanation |
---|---|---|
Abelian group | No | |
Nilpotent group | No | |
Metacyclic group | No | |
Supersolvable group | No | |
Solvable group | Yes | Length three, commutator subgroup is the quaternion group, next commutator subgroup is center. |
Other properties
Property | Satisfied? | Explanation |
---|---|---|
T-group | No | |
Monolithic group | Yes | The center of order two is the unique minimal normal subgroup. |
One-headed group | Yes | The commutator subgroup, which is a quaternion group |
Group having subgroups of all orders dividing the group order | No | |
Schur-trivial group | Yes | PLACEHOLDER FOR INFORMATION TO BE FILLED IN: [SHOW MORE] |
Elements
Further information: element structure of special linear group:SL(2,3)
Summary
Item | Value |
---|---|
order of the whole group (total number of elements) | 24 |
conjugacy class sizes | 1,1,4,4,4,4,6 grouped form: 1 (2 times), 4 (4 times), 6 (1 time) maximum: 6, number of conjugacy classes: 7, lcm: 12 |
order statistics | 1 of order 1, 1 of order 2, 8 of order 3, 6 of order 4, 8 of order 6 maximum: 6, lcm (exponent of the whole group): 12 |
Conjugacy classes
Note that since we are over field:F3, , so all the s below can be rewritten as s.
COMBINATORIAL BREAKDOWN TABLE: The table below breaks down a collection into various classes or types and provides information on the counts for each type. For some of the columns, totals provide a sanity check that all elements or classes have been accounted for. In this case, the table gives information on conjugacy class structure.
Conjugacy class representative | Conjugacy class size | List of all elements of conjugacy class | Order of elements in conjugacy class |
---|---|---|---|
1 | 1 | ||
1 | 2 | ||
4 | [SHOW MORE] | 3 | |
4 | [SHOW MORE] | 3 | |
4 | [SHOW MORE] | 6 | |
4 | [SHOW MORE] | 6 | |
6 | [SHOW MORE] | 4 | |
Total | 24 (order of the group) | -- | -- |
Automorphism classes
COMBINATORIAL BREAKDOWN TABLE: The table below breaks down a collection into various classes or types and provides information on the counts for each type. For some of the columns, totals provide a sanity check that all elements or classes have been accounted for. In this case, the table gives information on automorphism class structure.
Below are the orbits under the action of the automorphism group, i.e., the automorphism classes of elements of the group.
List of representatives for each conjugacy class in the automorphism class | Number of conjugacy classes in the automorphism class | Size of each conjugacy class | Automorphism class size | Order of elements in conjugacy class |
---|---|---|---|---|
1 | 1 | 1 | 1 | |
1 | 1 | 1 | 2 | |
, | 2 | 4 | 8 | 3 |
, | 2 | 4 | 8 | 6 |
1 | 6 | 6 | 4 | |
Total | 7 (number of conjugacy classes) | -- | 24 (order of the group) | -- |
Endomorphisms
Automorphisms
The automorphism group of is isomorphic to the symmetric group of degree four. The inner automorphism group, which is the quotient of by its center, and is also the projective special linear group , is isomorphic to the alternating group of degree four.
To see how the outer automorphisms act, we can view as a subgroup of index two in , the general linear group of order two over the field of three elements. The inner automorphism group, which is , is isomorphic to the symmetric group of degree four. Since is a normal subgroup, and since its center equals the center of , the automorphisms of all restrict to automorphisms of . has no other automorphisms.
Subgroups
Further information: Subgroup structure of special linear group:SL(2,3)
Quick summary
Item | Value |
---|---|
number of subgroups | 15 |
number of conjugacy classes of subgroups | 7 |
number of automorphism classes of subgroups | 7 |
isomorphism classes of Sylow subgroups, corresponding fusion systems, and Sylow numbers | 2-Sylow: quaternion group (order 8) as Q8 in SL(2,3) with its non-inner fusion system (see non-inner fusion system for quaternion group), Sylow number 1 3-Sylow: cyclic group:Z3 with its non-inner fusion system, Sylow number 4 |
Hall subgroups | The order has only two prime divisors, so no possibility of Hall subgroups other than trivial subgroup, whole group, and Sylow subgroups |
maximal subgroups | There are maximal subgroups of orders 6 (Z6 in SL(2,3)) and 8 (2-Sylow subgroup of special linear group:SL(2,3)) |
normal subgroups | There are two proper nontrivial normal subgroups: center of special linear group:SL(2,3) and 2-Sylow subgroup of special linear group:SL(2,3) |
Table classifying subgroups up to automorphism
Note that, in the matrices, -1 can be written as 2 since elements are taken modulo 3.
Automorphism class of subgroups | Representative subgroup | Isomorphism class | Order of subgroups | Index of subgroups | Number of conjugacy classes (=1 iff automorph-conjugate subgroup) | Size of each conjugacy class (=1 iff normal subgroup) | Total number of subgroups (=1 iff characteristic subgroup) | Isomorphism class of quotient (if exists) | Subnormal depth (if subnormal) | Note |
---|---|---|---|---|---|---|---|---|---|---|
trivial subgroup | trivial group | 1 | 24 | 1 | 1 | 1 | special linear group:SL(2,3) | 1 | trivial | |
center of special linear group:SL(2,3) | cyclic group:Z2 | 2 | 12 | 1 | 1 | 1 | alternating group:A4 | 1 | ||
Z4 in SL(2,3) | cyclic group:Z4 | 4 | 6 | 1 | 3 | 3 | -- | 2 | ||
2-Sylow subgroup of special linear group:SL(2,3) | quaternion group | 8 | 3 | 1 | 1 | 1 | cyclic group:Z3 | 1 | 2-Sylow | |
Z3 in SL(2,3) | cyclic group:Z3 | 3 | 8 | 1 | 4 | 4 | -- | -- | 3-Sylow | |
Z6 in SL(2,3) | cyclic group:Z6 | 6 | 4 | 1 | 4 | 4 | -- | -- | 3-Sylow normalizer | |
whole group | all elements | special linear group:SL(2,3) | 24 | 1 | 1 | 1 | 1 | trivial group | 0 | |
Total (7 rows) | -- | -- | -- | -- | 7 | -- | 15 | -- | -- | -- |
Subgroup-defining functions
Supergroups
The special linear group is a subgroup of the general linear group . It is also a subgroup of for any prime power (note that need not be a power of ). For full proof, refer: SL(2,3) is a subgroup of any special linear group, Dickson's theorem
GAP implementation
Group ID
This finite group has order 24 and has ID 3 among the groups of order 24 in GAP's SmallGroup library. For context, there are 15 groups of order 24. It can thus be defined using GAP's SmallGroup function as:
SmallGroup(24,3)
For instance, we can use the following assignment in GAP to create the group and name it :
gap> G := SmallGroup(24,3);
Conversely, to check whether a given group is in fact the group we want, we can use GAP's IdGroup function:
IdGroup(G) = [24,3]
or just do:
IdGroup(G)
to have GAP output the group ID, that we can then compare to what we want.
Other descriptions
Description | Functions used |
---|---|
SL(2,3) or SpecialLinearGroup(2,3) |
SL |
SchurCover(AlternatingGroup(4)) | SchurCover, AlternatingGroup |
Description by presentation
F := FreeGroup(3); G := F/[F.1^3*F.2^(-3), F.2^3*F.3^(-2), F.1^3*(F.1*F.2*F.3)^(-1)];