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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 = | 1 7 8 8 |
     | 0 4 6 6 |
     | 0 8 4 4 |
     | 2 6 9 6 |
     | 1 4 7 6 |
     | 2 2 7 5 |

              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 = subquotient (| 2 21 64 168 |, | 22 1365 0 840 |)
                  | 0 12 48 126 |  | 0  780  0 630 |
                  | 0 24 32 84  |  | 0  1560 0 420 |
                  | 4 18 72 126 |  | 44 1170 0 630 |
                  | 2 12 56 126 |  | 22 780  0 630 |
                  | 4 6  56 105 |  | 44 390  0 525 |

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

          ZZ   ZZ    ZZ
o3 = ZZ + -- + -- + ----
           5   11   5*13

o3 : Expression of class Sum