torsionSubmodule -- create the torsion submodule of a module

Synopsis

Usage:

torsionSubmodule( M1 )
Inputs:
- M1, a module,
Optional inputs:
- Strategy => a symbol, default value NoStrategy, specify a strategy for the internal call to reflexify
- KnownDomain => a Boolean value, default value false, assume the ambient ring is a domain for the internal call to reflexify
Outputs:
- a module,

Description

Finds the torsion submodule of a module. It does this by computing the kernel of the map from M1 to its reflexification. The options Strategy and KnownDomain are passed along when the function reflexify is called.

i1 : R = QQ[x,y];

i2 : m = ideal(x,y);

o2 : Ideal of R

i3 : M = (R^1/m) ++ R^1

o3 = cokernel | x y |
              | 0 0 |

                            2
o3 : R-module, quotient of R

i4 : prune torsionSubmodule M

o4 = cokernel | y x |

                            1
o4 : R-module, quotient of R

Ways to use torsionSubmodule :

torsionSubmodule(Module)

For the programmer

The object torsionSubmodule is a method function with options.

torsionSubmodule -- create the torsion submodule of a module

Synopsis

Description

See also

Ways to use torsionSubmodule :

For the programmer