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randomSimplicialMap(SimplicialModule,SimplicialModule) -- a random map of simplicial modules

Description

A random simplicial module map $f : C \to D$ is obtained from choosing a random map of the underlying normalizations, which uses the randomComplexMap command.

i1 : S = ZZ/101[a..c]

o1 = S

o1 : PolynomialRing
i2 : C = simplicialModule(freeResolution coker matrix{{a*b, a*c, b*c}}, 3, Degeneracy => true)

      1      4      9      16
o2 = S  <-- S  <-- S  <-- S  <-- ...
                           
     0      1      2      3

o2 : SimplicialModule
i3 : D = simplicialModule(freeResolution coker vars S, Degeneracy => true)

      1      4      10      20
o3 = S  <-- S  <-- S   <-- S  <-- ...
                            
     0      1      2       3

o3 : SimplicialModule
i4 : f = randomSimplicialMap(D,C)

          1              1
o4 = 0 : S  <---------- S  : 0
               | 24 |

          4                                                         4
     1 : S  <----------------------------------------------------- S  : 1
               {0} | 24 0            0            0            |
               {1} | 0  -36a-30b-29c -29a-24b-38c -39a-18b-13c |
               {1} | 0  19a+19b-10c  -16a+39b+21c -43a-15b-28c |
               {1} | 0  -29a-8b-22c  34a+19b-47c  -47a+38b+2c  |

          10                                                                                                                          9
     2 : S   <---------------------------------------------------------------------------------------------------------------------- S  : 2
                {0} | 24 0            0            0            0            0            0            0            0            |
                {1} | 0  -36a-30b-29c -29a-24b-38c -39a-18b-13c 0            0            0            0            0            |
                {1} | 0  19a+19b-10c  -16a+39b+21c -43a-15b-28c 0            0            0            0            0            |
                {1} | 0  -29a-8b-22c  34a+19b-47c  -47a+38b+2c  0            0            0            0            0            |
                {1} | 0  0            0            0            -36a-30b-29c -29a-24b-38c -39a-18b-13c 0            0            |
                {1} | 0  0            0            0            19a+19b-10c  -16a+39b+21c -43a-15b-28c 0            0            |
                {1} | 0  0            0            0            -29a-8b-22c  34a+19b-47c  -47a+38b+2c  0            0            |
                {2} | 0  0            0            0            0            0            0            16a+22b+45c  7a+15b-23c   |
                {2} | 0  0            0            0            0            0            0            -34a-48b-47c 39a+43b-17c  |
                {2} | 0  0            0            0            0            0            0            47a+19b-16c  -11a+48b+36c |

          20                                                                                                                                                                                                                     16
     3 : S   <----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- S   : 3
                {0} | 24 0            0            0            0            0            0            0            0            0            0            0            0            0            0            0            |
                {1} | 0  -36a-30b-29c -29a-24b-38c -39a-18b-13c 0            0            0            0            0            0            0            0            0            0            0            0            |
                {1} | 0  19a+19b-10c  -16a+39b+21c -43a-15b-28c 0            0            0            0            0            0            0            0            0            0            0            0            |
                {1} | 0  -29a-8b-22c  34a+19b-47c  -47a+38b+2c  0            0            0            0            0            0            0            0            0            0            0            0            |
                {1} | 0  0            0            0            -36a-30b-29c -29a-24b-38c -39a-18b-13c 0            0            0            0            0            0            0            0            0            |
                {1} | 0  0            0            0            19a+19b-10c  -16a+39b+21c -43a-15b-28c 0            0            0            0            0            0            0            0            0            |
                {1} | 0  0            0            0            -29a-8b-22c  34a+19b-47c  -47a+38b+2c  0            0            0            0            0            0            0            0            0            |
                {1} | 0  0            0            0            0            0            0            -36a-30b-29c -29a-24b-38c -39a-18b-13c 0            0            0            0            0            0            |
                {1} | 0  0            0            0            0            0            0            19a+19b-10c  -16a+39b+21c -43a-15b-28c 0            0            0            0            0            0            |
                {1} | 0  0            0            0            0            0            0            -29a-8b-22c  34a+19b-47c  -47a+38b+2c  0            0            0            0            0            0            |
                {2} | 0  0            0            0            0            0            0            0            0            0            16a+22b+45c  7a+15b-23c   0            0            0            0            |
                {2} | 0  0            0            0            0            0            0            0            0            0            -34a-48b-47c 39a+43b-17c  0            0            0            0            |
                {2} | 0  0            0            0            0            0            0            0            0            0            47a+19b-16c  -11a+48b+36c 0            0            0            0            |
                {2} | 0  0            0            0            0            0            0            0            0            0            0            0            16a+22b+45c  7a+15b-23c   0            0            |
                {2} | 0  0            0            0            0            0            0            0            0            0            0            0            -34a-48b-47c 39a+43b-17c  0            0            |
                {2} | 0  0            0            0            0            0            0            0            0            0            0            0            47a+19b-16c  -11a+48b+36c 0            0            |
                {2} | 0  0            0            0            0            0            0            0            0            0            0            0            0            0            16a+22b+45c  7a+15b-23c   |
                {2} | 0  0            0            0            0            0            0            0            0            0            0            0            0            0            -34a-48b-47c 39a+43b-17c  |
                {2} | 0  0            0            0            0            0            0            0            0            0            0            0            0            0            47a+19b-16c  -11a+48b+36c |
                {3} | 0  0            0            0            0            0            0            0            0            0            0            0            0            0            0            0            |

o4 : SimplicialModuleMap
i5 : assert isWellDefined f
i6 : assert not isCommutative f

When the random element is chosen with option Cycle => true, the associated map of simplicial modules commutes with the face/degeneracy map.

i7 : g = randomSimplicialMap(D,C, Cycle => true)

          1               1
o7 = 0 : S  <----------- S  : 0
               | -50 |

          4                                             4
     1 : S  <----------------------------------------- S  : 1
               {0} | -50 0       0        0        |
               {1} | 0   40b-35c -46b+18c 28b+3c   |
               {1} | 0   11a-11c 46a+22c  -28a-37c |
               {1} | 0   35a+11b 33a-22b  -3a-13b  |

          10                                                                                                 9
     2 : S   <--------------------------------------------------------------------------------------------- S  : 2
                {0} | -50 0       0        0        0       0        0        0            0            |
                {1} | 0   40b-35c -46b+18c 28b+3c   0       0        0        0            0            |
                {1} | 0   11a-11c 46a+22c  -28a-37c 0       0        0        0            0            |
                {1} | 0   35a+11b 33a-22b  -3a-13b  0       0        0        0            0            |
                {1} | 0   0       0        0        40b-35c -46b+18c 28b+3c   0            0            |
                {1} | 0   0       0        0        11a-11c 46a+22c  -28a-37c 0            0            |
                {1} | 0   0       0        0        35a+11b 33a-22b  -3a-13b  0            0            |
                {2} | 0   0       0        0        0       0        0        46b-49c      -28a-46b+17c |
                {2} | 0   0       0        0        0       0        0        -30b-35c     -3a+b        |
                {2} | 0   0       0        0        0       0        0        -38a-22b-11c -47a+22b     |

          20                                                                                                                                                                               16
     3 : S   <--------------------------------------------------------------------------------------------------------------------------------------------------------------------------- S   : 3
                {0} | -50 0       0        0        0       0        0        0       0        0        0            0            0            0            0            0            |
                {1} | 0   40b-35c -46b+18c 28b+3c   0       0        0        0       0        0        0            0            0            0            0            0            |
                {1} | 0   11a-11c 46a+22c  -28a-37c 0       0        0        0       0        0        0            0            0            0            0            0            |
                {1} | 0   35a+11b 33a-22b  -3a-13b  0       0        0        0       0        0        0            0            0            0            0            0            |
                {1} | 0   0       0        0        40b-35c -46b+18c 28b+3c   0       0        0        0            0            0            0            0            0            |
                {1} | 0   0       0        0        11a-11c 46a+22c  -28a-37c 0       0        0        0            0            0            0            0            0            |
                {1} | 0   0       0        0        35a+11b 33a-22b  -3a-13b  0       0        0        0            0            0            0            0            0            |
                {1} | 0   0       0        0        0       0        0        40b-35c -46b+18c 28b+3c   0            0            0            0            0            0            |
                {1} | 0   0       0        0        0       0        0        11a-11c 46a+22c  -28a-37c 0            0            0            0            0            0            |
                {1} | 0   0       0        0        0       0        0        35a+11b 33a-22b  -3a-13b  0            0            0            0            0            0            |
                {2} | 0   0       0        0        0       0        0        0       0        0        46b-49c      -28a-46b+17c 0            0            0            0            |
                {2} | 0   0       0        0        0       0        0        0       0        0        -30b-35c     -3a+b        0            0            0            0            |
                {2} | 0   0       0        0        0       0        0        0       0        0        -38a-22b-11c -47a+22b     0            0            0            0            |
                {2} | 0   0       0        0        0       0        0        0       0        0        0            0            46b-49c      -28a-46b+17c 0            0            |
                {2} | 0   0       0        0        0       0        0        0       0        0        0            0            -30b-35c     -3a+b        0            0            |
                {2} | 0   0       0        0        0       0        0        0       0        0        0            0            -38a-22b-11c -47a+22b     0            0            |
                {2} | 0   0       0        0        0       0        0        0       0        0        0            0            0            0            46b-49c      -28a-46b+17c |
                {2} | 0   0       0        0        0       0        0        0       0        0        0            0            0            0            -30b-35c     -3a+b        |
                {2} | 0   0       0        0        0       0        0        0       0        0        0            0            0            0            -38a-22b-11c -47a+22b     |
                {3} | 0   0       0        0        0       0        0        0       0        0        0            0            0            0            0            0            |

o7 : SimplicialModuleMap
i8 : assert isWellDefined g
i9 : assert isCommutative g
i10 : assert isSimplicialMorphism g

When the random element is chosen with option Boundary => true, the associated map of simplicial modules is a simplicial null homotopy.

i11 : h = randomSimplicialMap(D,C, Boundary => true)

           1         1
o11 = 0 : S  <----- S  : 0
                0

           4                                           4
      1 : S  <--------------------------------------- S  : 1
                {0} | 0 0       0        0        |
                {1} | 0 23b+7c  -29b+47c 37b+13c  |
                {1} | 0 -23a-2c 29a-15c  -37a+10c |
                {1} | 0 -7a+2b  -47a+15b -13a-10b |

           10                                                                                             9
      2 : S   <----------------------------------------------------------------------------------------- S  : 2
                 {0} | 0 0       0        0        0       0        0        0          0            |
                 {1} | 0 23b+7c  -29b+47c 37b+13c  0       0        0        0          0            |
                 {1} | 0 -23a-2c 29a-15c  -37a+10c 0       0        0        0          0            |
                 {1} | 0 -7a+2b  -47a+15b -13a-10b 0       0        0        0          0            |
                 {1} | 0 0       0        0        23b+7c  -29b+47c 37b+13c  0          0            |
                 {1} | 0 0       0        0        -23a-2c 29a-15c  -37a+10c 0          0            |
                 {1} | 0 0       0        0        -7a+2b  -47a+15b -13a-10b 0          0            |
                 {2} | 0 0       0        0        0       0        0        29b-48c    -37a-29b-18c |
                 {2} | 0 0       0        0        0       0        0        24b+7c     -13a-36b     |
                 {2} | 0 0       0        0        0       0        0        30a+15b-2c -28a-15b     |

           20                                                                                                                                                                       16
      3 : S   <------------------------------------------------------------------------------------------------------------------------------------------------------------------- S   : 3
                 {0} | 0 0       0        0        0       0        0        0       0        0        0          0            0          0            0          0            |
                 {1} | 0 23b+7c  -29b+47c 37b+13c  0       0        0        0       0        0        0          0            0          0            0          0            |
                 {1} | 0 -23a-2c 29a-15c  -37a+10c 0       0        0        0       0        0        0          0            0          0            0          0            |
                 {1} | 0 -7a+2b  -47a+15b -13a-10b 0       0        0        0       0        0        0          0            0          0            0          0            |
                 {1} | 0 0       0        0        23b+7c  -29b+47c 37b+13c  0       0        0        0          0            0          0            0          0            |
                 {1} | 0 0       0        0        -23a-2c 29a-15c  -37a+10c 0       0        0        0          0            0          0            0          0            |
                 {1} | 0 0       0        0        -7a+2b  -47a+15b -13a-10b 0       0        0        0          0            0          0            0          0            |
                 {1} | 0 0       0        0        0       0        0        23b+7c  -29b+47c 37b+13c  0          0            0          0            0          0            |
                 {1} | 0 0       0        0        0       0        0        -23a-2c 29a-15c  -37a+10c 0          0            0          0            0          0            |
                 {1} | 0 0       0        0        0       0        0        -7a+2b  -47a+15b -13a-10b 0          0            0          0            0          0            |
                 {2} | 0 0       0        0        0       0        0        0       0        0        29b-48c    -37a-29b-18c 0          0            0          0            |
                 {2} | 0 0       0        0        0       0        0        0       0        0        24b+7c     -13a-36b     0          0            0          0            |
                 {2} | 0 0       0        0        0       0        0        0       0        0        30a+15b-2c -28a-15b     0          0            0          0            |
                 {2} | 0 0       0        0        0       0        0        0       0        0        0          0            29b-48c    -37a-29b-18c 0          0            |
                 {2} | 0 0       0        0        0       0        0        0       0        0        0          0            24b+7c     -13a-36b     0          0            |
                 {2} | 0 0       0        0        0       0        0        0       0        0        0          0            30a+15b-2c -28a-15b     0          0            |
                 {2} | 0 0       0        0        0       0        0        0       0        0        0          0            0          0            29b-48c    -37a-29b-18c |
                 {2} | 0 0       0        0        0       0        0        0       0        0        0          0            0          0            24b+7c     -13a-36b     |
                 {2} | 0 0       0        0        0       0        0        0       0        0        0          0            0          0            30a+15b-2c -28a-15b     |
                 {3} | 0 0       0        0        0       0        0        0       0        0        0          0            0          0            0          0            |

o11 : SimplicialModuleMap
i12 : assert isWellDefined h
i13 : assert isCommutative h
i14 : assert isSimplicialMorphism h
i15 : assert isNullHomotopic normalize h
i16 : nullHomotopy normalize h

           3         1
o16 = 1 : S  <----- S  : 0
                0

           3                           3
      2 : S  <----------------------- S  : 1
                {2} | -23 29  -37 |
                {2} | -7  -47 -13 |
                {2} | 2   15  -10 |

           1                      2
      3 : S  <------------------ S  : 2
                {3} | 30 -18 |

o16 : ComplexMap

When the degree of the random element is chosen with a specific degree, the associated map of simplicial modules will be a well-defined degree 0 simplicial morphism mapping to the Dold-Kan image of the shift of the normalization. Thus, even when specifying nonzero degree this constructor will still yield a simplicial morphism.

i17 : p = randomSimplicialMap(D, C, Cycle => true, Degree => -1)

           1                                                                                                   3
o17 = 0 : S  <----------------------------------------------------------------------------------------------- S  : 0
                | 19a2-30ab+36b2+40ac+4bc-32c2 36a2+42ab-33b2+13ac-30bc+9c2 20a2+12ab-44b2-13ac-16bc+26c2 |

           4                                                                                                                                                                   5
      1 : S  <--------------------------------------------------------------------------------------------------------------------------------------------------------------- S  : 1
                {0} | 19a2-30ab+36b2+40ac+4bc-32c2 36a2+42ab-33b2+13ac-30bc+9c2 20a2+12ab-44b2-13ac-16bc+26c2 0                            0                              |
                {1} | 0                            0                            0                             -10ab-31b2-20ac+31bc-39c2    -20a2+24ab-48b2-30ac-15bc+39c2 |
                {1} | 0                            0                            0                             -26a2-11ab+33b2+34bc+4c2     33ab-33b2-49ac-19bc+17c2       |
                {1} | 0                            0                            0                             39a2+27ab+32b2-22ac-9bc-32c2 43a2-8ab-11b2+36ac-8bc         |

           10                                                                                                                                                                                                                               7
      2 : S   <--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- S  : 2
                 {0} | 19a2-30ab+36b2+40ac+4bc-32c2 36a2+42ab-33b2+13ac-30bc+9c2 20a2+12ab-44b2-13ac-16bc+26c2 0                            0                              0                            0                              |
                 {1} | 0                            0                            0                             -10ab-31b2-20ac+31bc-39c2    -20a2+24ab-48b2-30ac-15bc+39c2 0                            0                              |
                 {1} | 0                            0                            0                             -26a2-11ab+33b2+34bc+4c2     33ab-33b2-49ac-19bc+17c2       0                            0                              |
                 {1} | 0                            0                            0                             39a2+27ab+32b2-22ac-9bc-32c2 43a2-8ab-11b2+36ac-8bc         0                            0                              |
                 {1} | 0                            0                            0                             0                            0                              -10ab-31b2-20ac+31bc-39c2    -20a2+24ab-48b2-30ac-15bc+39c2 |
                 {1} | 0                            0                            0                             0                            0                              -26a2-11ab+33b2+34bc+4c2     33ab-33b2-49ac-19bc+17c2       |
                 {1} | 0                            0                            0                             0                            0                              39a2+27ab+32b2-22ac-9bc-32c2 43a2-8ab-11b2+36ac-8bc         |
                 {2} | 0                            0                            0                             0                            0                              0                            0                              |
                 {2} | 0                            0                            0                             0                            0                              0                            0                              |
                 {2} | 0                            0                            0                             0                            0                              0                            0                              |

           20                                                                                                                                                                                                                                                                                           9
      3 : S   <--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- S  : 3
                 {0} | 19a2-30ab+36b2+40ac+4bc-32c2 36a2+42ab-33b2+13ac-30bc+9c2 20a2+12ab-44b2-13ac-16bc+26c2 0                            0                              0                            0                              0                            0                              |
                 {1} | 0                            0                            0                             -10ab-31b2-20ac+31bc-39c2    -20a2+24ab-48b2-30ac-15bc+39c2 0                            0                              0                            0                              |
                 {1} | 0                            0                            0                             -26a2-11ab+33b2+34bc+4c2     33ab-33b2-49ac-19bc+17c2       0                            0                              0                            0                              |
                 {1} | 0                            0                            0                             39a2+27ab+32b2-22ac-9bc-32c2 43a2-8ab-11b2+36ac-8bc         0                            0                              0                            0                              |
                 {1} | 0                            0                            0                             0                            0                              -10ab-31b2-20ac+31bc-39c2    -20a2+24ab-48b2-30ac-15bc+39c2 0                            0                              |
                 {1} | 0                            0                            0                             0                            0                              -26a2-11ab+33b2+34bc+4c2     33ab-33b2-49ac-19bc+17c2       0                            0                              |
                 {1} | 0                            0                            0                             0                            0                              39a2+27ab+32b2-22ac-9bc-32c2 43a2-8ab-11b2+36ac-8bc         0                            0                              |
                 {1} | 0                            0                            0                             0                            0                              0                            0                              -10ab-31b2-20ac+31bc-39c2    -20a2+24ab-48b2-30ac-15bc+39c2 |
                 {1} | 0                            0                            0                             0                            0                              0                            0                              -26a2-11ab+33b2+34bc+4c2     33ab-33b2-49ac-19bc+17c2       |
                 {1} | 0                            0                            0                             0                            0                              0                            0                              39a2+27ab+32b2-22ac-9bc-32c2 43a2-8ab-11b2+36ac-8bc         |
                 {2} | 0                            0                            0                             0                            0                              0                            0                              0                            0                              |
                 {2} | 0                            0                            0                             0                            0                              0                            0                              0                            0                              |
                 {2} | 0                            0                            0                             0                            0                              0                            0                              0                            0                              |
                 {2} | 0                            0                            0                             0                            0                              0                            0                              0                            0                              |
                 {2} | 0                            0                            0                             0                            0                              0                            0                              0                            0                              |
                 {2} | 0                            0                            0                             0                            0                              0                            0                              0                            0                              |
                 {2} | 0                            0                            0                             0                            0                              0                            0                              0                            0                              |
                 {2} | 0                            0                            0                             0                            0                              0                            0                              0                            0                              |
                 {2} | 0                            0                            0                             0                            0                              0                            0                              0                            0                              |
                 {3} | 0                            0                            0                             0                            0                              0                            0                              0                            0                              |

o17 : SimplicialModuleMap
i18 : assert isWellDefined p
i19 : assert isCommutative p
i20 : assert isSimplicialMorphism p

Given an internal degree, the random element is constructed as maps of modules with this degree.

i21 : q = randomSimplicialMap(D, C, Boundary => true, InternalDegree => 2);
i22 : assert isCommutative q
i23 : assert isSimplicialMorphism q
i24 : source q === C

o24 = false
i25 : target q === D

o25 = false
i26 : assert isNullHomotopic normalize q

Ways to use this method:


The source of this document is in /build/reproducible-path/macaulay2-1.26.05+ds/M2/Macaulay2/packages/SimplicialModules/SimplicialModuleDOC.m2:3041:0.