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Macaulay2Doc :: factor(Module)

factor(Module) -- factor a ZZ-module

Synopsis

Description

The ring of M must be ZZ.

In the following example we construct a module with a known (but disguised) factorization.

i1 : f = random(ZZ^6, ZZ^4)

o1 = | 6 9 9 9 |
     | 2 4 6 8 |
     | 9 5 6 5 |
     | 5 3 1 7 |
     | 6 6 1 4 |
     | 5 2 6 7 |

              6        4
o1 : Matrix ZZ  <--- ZZ
i2 : M = subquotient ( f * diagonalMatrix{2,3,8,21}, f * diagonalMatrix{2*11,3*5*13,0,21*5} )

o2 = image 0

                               6
o2 : ZZ-module, submodule of ZZ
i3 : factor M

o3 = 0

o3 : Expression of class Sum