1 A B C D E F G H I J K L M N O P Q R S T U V W X Y
1 A B C D E F G H I J K L M N O P Q R S T U V W X Y
A L U K M X R S W Q T Y F O 1 V N C J I H G B E P D
B V 1 H R I M P C E Y T O F U L G W D X K N A Q S J
C Q T 1 X M S R V L U N I E K W Y A G F B J H O D P
D Y E F 1 B C H G J I L K N M P O R Q T S W X U V A
E X D G Q J N O F B A S P C W K H U 1 V L M Y R T I
F R S D V N T Q X K W M J B L U A Y H C E I G P 1 O
G U L E T C V 1 Y P M W B J S R I X O N D A F K Q H
H W K B S F X D A O N U E I T Q J V P M 1 Y C L R G
I S R P W Y U L M 1 V X G H Q T C N B A O F J D K E
J T Q O U A W K N D X V H G R S F M E Y P C I 1 L B
K C H A P O I J B F G 1 Q X Y E D L S R U T W V M N
L F G Y O P J I E C H D R V A B 1 K T Q W S U X N M
M D X R A U K W S T Q F Y 1 O N V J C H I E P G B L
N 1 V Q Y W L U T S R C A D P M X I F G J B O H E K
O M P J L G Y E I H C R D A V 1 B T K W Q X N S U F
P N O I K H A B J G F Q 1 Y X D E S L U R V M T W C
Q I J N E D G F O A B P S W C H K 1 U L V R T M Y X
R J I M B 1 H C P Y E O T U F G L D W K X Q S N A V
S G F X H K B A D N O E U T I J Q P V 1 M L R Y C W
T H C V G L E Y 1 M P B W S J I R O X D N K Q A F U
U B A W J Q O N K X D H V R G F S E M P Y 1 L C I T
V O N T F S D X Q W K J M L B A U H Y E C P 1 I G R
W E Y U I R P M L V 1 G X Q H C T B N O A D K F J S
X P M S C T 1 V R U L I N K E Y W G A B F O D J H Q
Y K W L N V Q T U R S A C P D X M F I J G H E B O 1
$
1
b^2
ab^5
ab^6
a
b^5
b^6
ab
b
ab^10
b^10
ab^4
b^4
ab^11
b^11
ab^9
b^9
ab^8
b^8
ab^12
b^12
ab^3
ab^7
b^3
b^7
ab^2
Dihedral(13)
Relations:
a^2 = 1,
b^13 = 1,
b^a = b^12
集合运算表:
Operator Usage Meaning
# #S the number of elements in S
in x in S true if the element x is in S, else false
notin x notin S true if the element x is not in S, else false
cat S1 cat S2 the concatenation of sequences S1 and S2
join S1 join S2 the union of sets S1 and S2
meet S1 meet S2 the intersection of sets S1 and S2
diff S1 diff S2 the set of elements in set S1 but not in set S2
sdiff S1 sdiff S2 the symmetric difference of sets S1 and S2
subset S1 subset S2 true if S1 is a subset of S2, else false
关系表:
not not a true if a is false, else false
and a and b true if both a and b are true, else false
or a or b true if either a or b is true, else false
xor a xor b true if exactly one of a and b is true, else false
eq x eq y true if x is equal to y , else false
ne x ne y true if x is not equal to y , else false
lt x lt y true if x is less than y , else false
le x le y true if x is less than or equal to y , else false
gt x gt y true if x is greater than y , else false
ge x ge y true if x is greater than or equal to y , else false
小群表:
Size Construction Notes
1 SymmetricGroup(1) Trivial
2 SymmetricGroup(2) Also CyclicPermutationGroup(2)
3 CyclicPermutationGroup(3) Prime order
4 CyclicPermutationGroup(4) Cyclic
4 KleinFourGroup() Abelian, non-cyclic
5 CyclicPermutationGroup(5) Prime order
6 CyclicPermutationGroup(6) Cyclic
6 SymmetricGroup(3) Non-abelian, also DihedralGroup(3)
7 CyclicPermutationGroup(7) Prime order
8 CyclicPermutationGroup(8) Cyclic
8 D1=CyclicPermutationGroup(4)
D2=CyclicPermutationGroup(2)
G=direct product permgroups([D1,D2])
Abelian, non-cyclic
8 D1=CyclicPermutationGroup(2)
D2=CyclicPermutationGroup(2)
D3=CyclicPermutationGroup(2)
G=direct product permgroups([D1,D2,D3])
Abelian, non-cyclic
8 DihedralGroup(4) Non-abelian
8 PermutationGroup(["(1,2,5,6)(3,4,7,8)",
"(1,3,5,7)(2,8,6,4)" ])
Quaternions
The two generators are I and J
9 CyclicPermutationGroup(9) Cyclic
9 D1=CyclicPermutationGroup(3)
D2=CyclicPermutationGroup(3)
G=direct product permgroups([D1,D2])
Abelian, non-cyclic
10 CyclicPermutationGroup(10) Cyclic
10 DihedralGroup(5) Non-abelian
11 CyclicPermutationGroup(11) Prime order
12 CyclicPermutationGroup(12) Cyclic
12 D1=CyclicPermutationGroup(6)
D2=CyclicPermutationGroup(2)
G=direct product permgroups([D1,D2])
Abelian, non-cyclic
12 DihedralGroup(6) Non-abelian
12 AlternatingGroup(4) Non-abelian, symmetries of tetrahedron
12 PermutationGroup(["(1,2,3)(4,6)(5,7)",
"(1,2)(4,5,6,7)"])
Non-abelian
Semi-direct product Z3 o Z4
13 CyclicPermutationGroup(13) Prime order
14 CyclicPermutationGroup(14) Cyclic
14 DihedralGroup(7) Non-abelian
15 CyclicPermutationGroup(15) Cyclic
There is an extremely important class of operators called reduction operators.
These have the form &op and act on a set or sequence to reduce it to a
single element by repeated application of the binary operator op. Not all
binary operators have a corresponding reduction operator; the valid reduction
operators are as follows.
&+ &∗ &and &or &meet &join &cat
If S contains the elements α1, . . . , αn in that order3 then
&op S = (. . . ((α1 op α2) op α3) . . .) op αn.
Note that most of these operators are commutative (at least under common
circumstances). The exception is &cat , which concatenates the elements of the
set/sequence.
3For sets, the order is the internal iteration order, which corresponds to the order
used when printing.
344 Geoff Bailey
> &+[ k 2 : k in [1. . 24] ];
4900
> F 11 := GF(11);
> _<t> := PolynomialRing(F 11);
> &∗{ t − a : a in F 11 | not IsSquare(a) };
t^5 + 1
> P<a,b,c> := PolynomialRing(Integers(), 3);
> sympols := [ &+[ &∗S : S in Subsets({a,b,c }, k ) ] : k in [0. . 3] ];
> sympols ;
[
1,
a + b + c,
a*b + a*c + b*c,
a*b*c
]
> &and [ IsSymmetric(pol) : pol in sympols ];
true
> &cat [ “Hello,”, “ ”, “world!” ];
Hello, world!
> &meet [ { n : n in [2. . 104] | Modexp(x ,n,n) eq x } : x in {2, 3, 5} ]
> diff { n : n in [2. . 104] | IsPrime(n) };
{ 561, 1105, 1729, 2465, 2821, 6601, 8911 }
When a set or sequence is empty then it may not be obvious what the result
of applying a reduction operator to it should be. The guiding principle is that
the result should be consistent, in the sense that (&op S) op x should produce
x when S is empty. Thus &+ produces 0 and &∗ produces 1, &and produces
true and &or produces false, and &join and &cat produce empty objects of the
appropriate types. It is not permissible to call &meet on an empty structure.
In the case of &+ and &∗, if they are called on an empty set or sequence
then the universe must have already been set. This is so that Magma can
determine in which structure the result should lie.