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Hom(ZZdFactorizationMap,ZZdFactorizationMap) -- the map of factorizations between Hom complexes

Description

The maps $f : C \to D$ and $g : E \to F$ of ZZ/d-graded factorizations induces the map $h = Hom(f,g) : Hom(D,E) \to Hom(C,F)$ defined by $\phi \mapsto g \phi f$.

i1 : S = ZZ/101[a,b];
i2 : R = S/(a^3+b^3);
i3 : m = ideal vars R

o3 = ideal (a, b)

o3 : Ideal of R
i4 : C = tailMF m

      2      2      2
o4 = S  <-- S  <-- S
                    
     0      1      0

o4 : ZZdFactorization
i5 : D = tailMF (m^2)

      3      3      3
o5 = S  <-- S  <-- S
                    
     0      1      0

o5 : ZZdFactorization
i6 : f = randomFactorizationMap(C,D)

          2                                         3
o6 = 0 : S  <------------------------------------- S  : 0
               {2} | 24a-36b -29a+19b -10a-29b |
               {3} | -30     19       -8       |

          2                                          3
     1 : S  <-------------------------------------- S  : 1
               {4} | -22a-29b -16a+39b 19a-47b  |
               {4} | -24a-38b 21a+34b  -39a-18b |

o6 : ZZdFactorizationMap
i7 : E = (dual C)

      2      2      2
o7 = S  <-- S  <-- S
                    
     0      1      0

o7 : ZZdFactorization
i8 : F = (dual D)

      3      3      3
o8 = S  <-- S  <-- S
                    
     0      1      0

o8 : ZZdFactorization
i9 : g = randomFactorizationMap(F,E)

          3                            2
o9 = 0 : S  <------------------------ S  : 0
               {-3} | -13a-43b 2  |
               {-3} | -15a-28b 16 |
               {-3} | -47a+38b 22 |

          3                                 2
     1 : S  <----------------------------- S  : 1
               {-5} | 45a-34b  -16a+7b |
               {-5} | -48a-47b 15a-23b |
               {-5} | 47a+19b  39a+43b |

o9 : ZZdFactorizationMap
i10 : h = Hom(f,g)

           18                                                                                                                      8
o10 = 0 : S   <------------------------------------------------------------------------------------------------------------------ S  : 0
                 {-6}  | 9a2-42ab-33b2   -48a-29b 14a+23b  -41 0               0              0               0               |
                 {-6}  | -44a2+31ab+2b2  20a-30b  -46a-32b -25 0               0              0               0               |
                 {-6}  | 17a2+22ab-46b2  -23a-16b 4a+29b   -47 0               0              0               0               |
                 {-6}  | 27a2+10ab+9b2   -43a-38b 45a+9b   -38 0               0              0               0               |
                 {-6}  | -31a2-22ab+27b2 -41a-b   -18a+27b -1  0               0              0               0               |
                 {-6}  | -50a2-25ab-15b2 32a-14b  -16a-15b -14 0               0              0               0               |
                 {-6}  | -29a2+ab-35b2   20a-43b  -3a-41b  16  0               0              0               0               |
                 {-6}  | -49a2-8ab-4b2   -42a-41b -19a-22b 27  0               0              0               0               |
                 {-6}  | 35a2+27ab-9b2   18a+32b  28a+b    -26 0               0              0               0               |
                 {-10} | 0               0        0        0   -20a2-49ab+24b2 -49a2-7ab+b2   -31a2-15ab+21b2 20a2-36ab-37b2  |
                 {-10} | 0               0        0        0   -46a2-2ab-50b2  27a2+30ab+40b2 -41a2-23ab+32b2 -44a2+18ab+35b2 |
                 {-10} | 0               0        0        0   24a2-37ab+46b2  50a2-44ab+35b2 17a2+20ab+15b2  27a2-11ab+18b2  |
                 {-10} | 0               0        0        0   13a2+24ab+13b2  47a2+29ab+30b2 -36a2-8ab+45b2  33a2-7ab-36b2   |
                 {-10} | 0               0        0        0   40a2+9ab+15b2   38a2-44ab-12b2 -2a2-7ab-18b2   -12a2-27ab-26b2 |
                 {-10} | 0               0        0        0   45a2-14ab-34b2  18a2-25ab+40b2 23a2+23ab-40b2  -11a2-7ab-48b2  |
                 {-10} | 0               0        0        0   -47a2+34ab+18b2 a2+24ab+26b2   38a2-11ab-6b2   -18a2-15ab+25b2 |
                 {-10} | 0               0        0        0   3a2-50ab+13b2   18a2+31ab+30b2 47a2+30ab-38b2  -21a2-21ab-10b2 |
                 {-10} | 0               0        0        0   16a2+30ab-16b2  -34a2+6ab+b2   15a2-29ab+39b2  6a2-45ab-34b2   |

           18                                                                                                                    8
      1 : S   <---------------------------------------------------------------------------------------------------------------- S  : 1
                 {-8} | 31a2+12ab-12b2  -20a2-37ab+50b2 37a-10b  25a+8b   0               0        0               0        |
                 {-8} | 41a2+6ab+25b2   44a2-19ab-20b2  -26a+4b  46a+17b  0               0        0               0        |
                 {-8} | -17a2+24ab-23b2 -27a2-32ab+33b2 -4a-36b  -42a-23b 0               0        0               0        |
                 {-8} | -8a2-23ab+40b2  41a2+2ab-32b2   -47a+40b a-32b    0               0        0               0        |
                 {-8} | 22a2-47ab-16b2  31a2-43ab+33b2  3a-16b   18a+33b  0               0        0               0        |
                 {-8} | 50a2-39ab+43b2  20a2+ab-9b2     16a+43b  -34a-9b  0               0        0               0        |
                 {-8} | 46a2-45ab+24b2  42a2+10ab+b2    -44a+31b -27a-45b 0               0        0               0        |
                 {-8} | 25a2-44ab-50b2  49a2+3ab+40b2   20a+28b  19a+18b  0               0        0               0        |
                 {-8} | -35a2+38ab+46b2 -14a2+46ab+35b2 -28a-50b 9a+41b   0               0        0               0        |
                 {-8} | 0               0               0        0        17a2-10ab-35b2  44a-43b  -9a2-11ab-18b2  48a-25b  |
                 {-8} | 0               0               0        0        -27a2-41ab-4b2  49a-41b  44a2-30ab+47b2  -20a+2b  |
                 {-8} | 0               0               0        0        -24a2-22ab-9b2  -21a+32b -17a2+35ab+30b2 23a+28b  |
                 {-8} | 0               0               0        0        -6a2+21ab-40b2  32a+23b  -30a2+32ab+48b2 -42a+33b |
                 {-8} | 0               0               0        0        -38a2+36ab-19b2 -47a-18b 12a2-13ab+43b2  -33a-39b |
                 {-8} | 0               0               0        0        -45a2+17ab+33b2 49a-50b  -23a2-8ab+21b2  43a-41b  |
                 {-8} | 0               0               0        0        45a2+4ab-b2     -38a-7b  -2a2+8ab+34b2   -23a+36b |
                 {-8} | 0               0               0        0        -18a2+29ab-3b2  -a+45b   21a2-49ab+b2    18a-15b  |
                 {-8} | 0               0               0        0        -16a2-2ab-32b2  -14a+24b -15a2+30ab-23b2 50a-8b   |

o10 : ZZdFactorizationMap
i11 : assert isWellDefined h

We illustrate the defining property of the map $h$ on a random element $\phi$ in degree zero.

i12 : e = randomFactorizationMap(source h, ZZdfactorization(S^1,2))

           8                                                                         1
o12 = 0 : S  <--------------------------------------------------------------------- S  : 0
                {-4} | -17a4-11a3b+48a2b2+36ab3+35b4                            |
                {-5} | 11a5-38a4b+33a3b2+40a2b3+11ab4+46b5                      |
                {-5} | -28a5+a4b-3a3b2+22a2b3-47ab4-23b5                        |
                {-6} | -7a6+2a5b+29a4b2-47a3b3+15a2b4-37ab5-13b6                |
                {-8} | -10a8+30a7b-18a6b2+39a5b3+27a4b4-22a3b5+32a2b6-9ab7-32b8 |
                {-8} | -20a8+24a7b-30a6b2-48a5b3-15a4b4+39a3b5+33ab7-49b8       |
                {-8} | -33a8-19a7b+17a6b2-20a5b3+44a4b4-39a3b5+36a2b6+9ab7-39b8 |
                {-8} | 4a8+13a7b-26a6b2+22a5b3-49a4b4-11a3b5-8a2b6+43ab7-8b8    |

           8
      1 : S  <----- 0 : 1
                0

o12 : ZZdFactorizationMap
i13 : phi = homomorphism e

           2                                                                                              2
o13 = 0 : S  <------------------------------------------------------------------------------------------ S  : 0
                {-2} | -17a4-11a3b+48a2b2+36ab3+35b4       -28a5+a4b-3a3b2+22a2b3-47ab4-23b5         |
                {-3} | 11a5-38a4b+33a3b2+40a2b3+11ab4+46b5 -7a6+2a5b+29a4b2-47a3b3+15a2b4-37ab5-13b6 |

           2                                                                                                                                  2
      1 : S  <------------------------------------------------------------------------------------------------------------------------------ S  : 1
                {-4} | -10a8+30a7b-18a6b2+39a5b3+27a4b4-22a3b5+32a2b6-9ab7-32b8 -33a8-19a7b+17a6b2-20a5b3+44a4b4-39a3b5+36a2b6+9ab7-39b8 |
                {-4} | -20a8+24a7b-30a6b2-48a5b3-15a4b4+39a3b5+33ab7-49b8       4a8+13a7b-26a6b2+22a5b3-49a4b4-11a3b5-8a2b6+43ab7-8b8    |

o13 : ZZdFactorizationMap
i14 : e == homomorphism'(phi)

o14 = true

If either of the arguments is a ZZdFactorization, that argument is understood to be the identity map on that factorization.

i15 : assert(Hom(f, C) == Hom(f, id_C))
i16 : assert(Hom(C, f) == Hom(id_C, f))

XXX write this text after writing doc for homomorphism and homomorphism'.

i17 : e = randomFactorizationMap(source h, ZZdfactorization(S^1, 2, Base => 1))

           8
o17 = 0 : S  <----- 0 : 0
                0

           8                                                                   1
      1 : S  <--------------------------------------------------------------- S  : 1
                {-6} | 36a6-3a5b-22a4b2-30a3b3+41a2b4+16ab5-28b6          |
                {-6} | -6a6+35a5b-9a4b2-35a3b3+6a2b4+40ab5+3b6            |
                {-7} | -31a7+25a6b-2a5b2-41a4b3-49a3b4-13a2b5+4ab6+30b7   |
                {-7} | -47a7+27a6b-40a5b2+37a4b3-35a3b4-31a2b5-39ab6-31b7 |
                {-6} | -48a6-29a5b-48a4b2+30a3b3-37a2b4+47ab5-49b6        |
                {-7} | 28a7-18a6b+46a5b2+a4b3+40a3b4-22a2b5+10ab6+7b7     |
                {-6} | 30a6+13a5b-17a4b2-13a3b3+3a2b4-41ab5+8b6           |
                {-7} | 8a7-29a6b+30a5b2-46a4b3+49a3b4-18a2b5+42ab6+23b7   |

o17 : ZZdFactorizationMap
i18 : phi = homomorphism e

           2                                                                                                             2
o18 = 1 : S  <--------------------------------------------------------------------------------------------------------- S  : 0
                {-4} | 36a6-3a5b-22a4b2-30a3b3+41a2b4+16ab5-28b6 -31a7+25a6b-2a5b2-41a4b3-49a3b4-13a2b5+4ab6+30b7   |
                {-4} | -6a6+35a5b-9a4b2-35a3b3+6a2b4+40ab5+3b6   -47a7+27a6b-40a5b2+37a4b3-35a3b4-31a2b5-39ab6-31b7 |

           2                                                                                                                2
      0 : S  <------------------------------------------------------------------------------------------------------------ S  : 1
                {-2} | -48a6-29a5b-48a4b2+30a3b3-37a2b4+47ab5-49b6    30a6+13a5b-17a4b2-13a3b3+3a2b4-41ab5+8b6         |
                {-3} | 28a7-18a6b+46a5b2+a4b3+40a3b4-22a2b5+10ab6+7b7 8a7-29a6b+30a5b2-46a4b3+49a3b4-18a2b5+42ab6+23b7 |

o18 : ZZdFactorizationMap
i19 : assert(degree phi == 1)
i20 : psi = homomorphism'(g * phi * f)

           18                                                                          1
o20 = 1 : S   <---------------------------------------------------------------------- S  : 0
                 {-8} | -25a8+19a7b+37a6b2-26a5b3-19a4b4+46a3b5+20a2b6-31ab7-39b8 |
                 {-8} | 43a8-2a7b-32a6b2+12a5b3+33a4b4-13a3b5+20a2b6+44ab7-45b8   |
                 {-8} | -32a8-14a7b+20a6b2-21a5b3-21a4b4+31a3b5-42a2b6+2ab7+28b8  |
                 {-8} | 33a8-38a7b+50a6b2-5a5b3+4a4b4-39a3b5-35a2b6+23ab7+34b8    |
                 {-8} | 30a8+5a6b2-33a5b3-7a4b4+14a3b5+9a2b6-28ab7+47b8           |
                 {-8} | 46a8-35a7b-8a6b2+a5b3-43a4b4-5a3b5+14a2b6-46ab7-35b8      |
                 {-8} | 3a8+13a7b+26a6b2+50a5b3-39a4b4-28a3b5+37a2b6+21ab7-40b8   |
                 {-8} | -2a8-44a7b-16a6b2-42a5b3-36a4b4-45a3b5-15a2b6-48ab7+16b8  |
                 {-8} | 24a8+26a7b+43a6b2-5a5b3-38a4b4-17a3b5+46a2b6-9ab7+15b8    |
                 {-8} | -25a8+8a7b-32a6b2-11a5b3-29a4b4+48a3b5-28a2b6-33ab7+12b8  |
                 {-8} | 10a8+21a7b-31a6b2+44a5b3-26a4b4-9a3b5+35a2b6-19ab7-28b8   |
                 {-8} | -36a8+22a7b+20a6b2-28a5b3+12a4b4-3a3b5+44a2b6+33ab7-34b8  |
                 {-8} | -49a8+27a7b+22a6b2-10a5b3+15a4b4-22a3b5-21a2b6+10ab7-32b8 |
                 {-8} | 2a8-26a7b-3a6b2-2a5b3-40a4b4+24a3b5-15a2b6-44ab7-50b8     |
                 {-8} | 46a8-32a7b+33a6b2-4a5b3-11a4b4+37a2b6-14ab7+15b8          |
                 {-8} | 34a8+42a7b-18a6b2+36a5b3+31a4b4+8a3b5+22a2b6+17ab7+11b8   |
                 {-8} | 6a8+17a7b-29a6b2-24a5b3-a4b4+45a3b5-17a2b6-50ab7-24b8     |
                 {-8} | -23a8+32a7b-44a6b2+5a5b3+37a4b4-49a3b5-11a2b6-26ab7+46b8  |

           18
      0 : S   <----- 0 : 1
                 0

o20 : ZZdFactorizationMap
i21 : i = map(ZZdfactorization(S^1, 2), source e, id_(source e), Degree => 1)

o21 = 1 : 0 <----- 0 : 0
               0

           1             1
      0 : S  <--------- S  : 1
                | 1 |

o21 : ZZdFactorizationMap
i22 : assert((degree h, degree e, degree psi, degree i) === (0, 0, 1, 1))

See also

Ways to use this method:

  • Hom(Matrix,ZZdFactorization)
  • Hom(Matrix,ZZdFactorizationMap)
  • Hom(Module,ZZdFactorizationMap)
  • Hom(Ring,ZZdFactorizationMap)
  • Hom(ZZdFactorization,Matrix)
  • Hom(ZZdFactorization,ZZdFactorizationMap)
  • Hom(ZZdFactorizationMap,Matrix)
  • Hom(ZZdFactorizationMap,Module)
  • Hom(ZZdFactorizationMap,Ring)
  • Hom(ZZdFactorizationMap,ZZdFactorization)
  • Hom(ZZdFactorizationMap,ZZdFactorizationMap) -- the map of factorizations between Hom complexes

The source of this document is in MatrixFactorizations/MatrixFactorizationsDOC.m2:3333:0.