CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutSign UpSign In

Real-time collaboration for Jupyter Notebooks, Linux Terminals, LaTeX, VS Code, R IDE, and more,
all in one place.

| Download

GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it

Views: 418346
1
<Chapter><Heading> Meataxe modules</Heading>
2
3
<Table Align="|l|" >
4
5
<Row>
6
<Item>
7
<Index>DesuspensionMtxModule</Index>
8
<C>DesuspensionMtxModule(M)</C>
9
<P/>
10
11
Inputs a meataxe module <M>M</M> over the field of <M>p</M> elements
12
and returns an FpG-module DM. The two modules are related mathematically
13
by the existence of a short exact sequence <M>DM \longrightarrow FM \longrightarrow M</M> with <M>FM</M> a free module. Thus the homological properties of <M>DM</M> are equal to those of <M>M</M> with a dimension shift.
14
<P/>
15
16
(If <M>G:=Group(M.generators)</M> is a <M>p</M>-group then <M>FM</M> is a
17
projective cover of <M>M</M> in the sense that the homomorphism
18
<M>FM \longrightarrow M</M> does not factor as <M>FM \longrightarrow P \longrightarrow M</M> for any projective module <M>P</M>.)
19
</Item>
20
</Row>
21
22
<Row>
23
<Item>
24
<Index>FpG&uscore;to&uscore;MtxModule</Index>
25
<C>FpG&uscore;to&uscore;MtxModule(M)</C>
26
<P/>
27
Inputs an FpG-module <M>M</M> and returns an isomorphic meataxe module.
28
</Item>
29
</Row>
30
31
<Row>
32
<Item>
33
<Index>GeneratorsOfMtxModule</Index>
34
<C>GeneratorsOfMtxModule(M)</C>
35
36
37
<P/>
38
Inputs a meataxe module <M>M</M> acting on, say, the vector space <M>V</M>.
39
The function
40
returns a minimal
41
list of row vectors in <M>V</M> which generate <M>V</M> as a <M>G</M>-module (where G=Group(M.generators) ).
42
</Item>
43
</Row>
44
45
</Table>
46
</Chapter>
47
48
49
50