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Set-Theoretic Operations in a Group
Set-Theoretic Operations in a Group
Subsections
Functions Relating to Group Order
Exponent(G) : GrpPC -> RngIntElt
The exponent of the group G.
FactoredIndex(G, H) : GrpPC, GrpPC -> [<RngIntElt, RngIntElt>]
The factored index of the subgroup H in the group G.
FactoredOrder(G) : GrpPC -> [<RngIntElt, RngIntElt>]
The factored order of the group G.
Index(G, H) : GrpPC, GrpPC -> RngIntElt
The index of the subgroup H in the group G, returned as an
ordinary integer.
Order(G) : GrpPC -> RngIntElt
# G : GrpPC -> RngIntElt
The order of the group G, returned as an ordinary integer.
Membership and Equality
g in G : GrpPCElt, GrpPC -> BoolElt
Given an element g and a group G, return true if g is an element
of G, false otherwise.
g notin G : GrpPCElt, GrpPC -> BoolElt
Given an element g and a group G, return true if g is not an
element of G, false otherwise.
S subset G : { GrpPCElt } , GrpPC -> BoolElt
Given an group G and a set S of elements belonging to a group H,
where G and H have some covering group, return true if S is
a subset of G, false otherwise.
S notsubset G : { GrpPCElt } , GrpPC -> BoolElt
Given a group G and a set S of elements belonging to a group H,
where G and H have some covering group, return true if S is
not a subset of G, false otherwise.
H subset G : GrpPC, GrpPC -> BoolElt
Given groups G and H, subgroups of some covering group, return
true if H is a subgroup of G, false otherwise.
H notsubset G : GrpPC, GrpPC -> BoolElt
Given groups G and H, subgroups of some covering group, return
true if H is not a subgroup of G, false otherwise.
G eq H : GrpPC, GrpPC -> BoolElt
Given groups G and H, subgroups of some covering group, return
true if G and H are the same group, false otherwise.
G ne H : GrpPC, GrpPC -> BoolElt
Given groups G and H, subgroups of some covering group, return
true if G and H are distinct groups, false otherwise.
Set Operations
NumberingMap(G) : GrpPC -> Map
A bijective mapping from the group G onto the set of integers {1 ... |G|}.
The actual mapping depends upon the current presentation for G.
Representative(G) : GrpPC -> GrpPCElt
Rep(G) : GrpPC -> GrpPCElt
A representative element of G.
RandomProcess(G) : GrpPC -> Process
Slots: RngIntElt Default: 10
Scramble: RngIntElt Default: 20
Create a process to generate randomly chosen elements from the
group G. The process uses an `expansion' procedure
to construct a set of elements corresponding to fairly long words in the
generators of G. At all times, N elements are stored where N is
the maximum of the specified value for Slots and Ngens(G) + 1.
Initially, these are just the generators of G and products of pairs
of generators of G. Random elements are now produced by successive
calls to Random(P), where P is the process created by this
function. Each such call chooses an element from the process and returns
it, replacing it with the product of it and another random element
(on the left or the right). Setting Scramble := m causes m
such operations to be performed before the process is returned.
Random(P) : Process -> GrpPCElt
Given a random element process P created by the function
RandomProcess(G) for the finite group G,
construct a random element of G by forming a
random product over the expanded generating set constructed when the
process was created.
Random(G) : GrpPC -> GrpPCElt
An element, randomly chosen, from the group G.
Example GrpPC_Set (H19E3)
Given the subgroups H and K of G,
construct the set product of the groups H and K.
> set_product := func<G, H, K | { G | x * y : x in H, y in K }>;
Given a subgroup H of the pc-group G, construct H as a set
of elements of G.
> elements := func<G, H | { G | x : x in H }>;
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