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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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