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SimplicialModuleMap || SimplicialModuleMap -- join or concatenate maps vertically

Description

Given simplicial module maps with the same source, this method constructs the associated map from the source to the direct sum of the targets.

First, we define some non-trivial maps of simplicial modules.

i1 : R = ZZ/101[a..d];
i2 : D1 = simplicialModule((freeResolution coker matrix{{a,b,c}})[1], Degeneracy => true)

      3      6      10
o2 = R  <-- R  <-- R  <-- ...
                    
     0      1      2

o2 : SimplicialModule
i3 : D2 = simplicialModule(freeResolution coker matrix{{a*b,a*c,b*c}}, Degeneracy => true)

      1      4      9
o3 = R  <-- R  <-- R <-- ...
                    
     0      1      2

o3 : SimplicialModule
i4 : C = simplicialModule(freeResolution coker matrix{{a^2,b^2,c*d}}, Degeneracy => true)

      1      4      10      20
o4 = R  <-- R  <-- R   <-- R  <-- ...
                            
     0      1      2       3

o4 : SimplicialModule
i5 : f = randomSimplicialMap(D1, C)

          3         1
o5 = 0 : R  <----- R  : 0
               0

          6                             4
     1 : R  <------------------------- R  : 1
               {1} | 0 0   0   0   |
               {1} | 0 0   0   0   |
               {1} | 0 0   0   0   |
               {2} | 0 24  -29 -10 |
               {2} | 0 -36 19  -29 |
               {2} | 0 -30 19  -8  |

          10                                                                                           10
     2 : R   <--------------------------------------------------------------------------------------- R   : 2
                {1} | 0 0   0   0   0   0   0   0                0                0               |
                {1} | 0 0   0   0   0   0   0   0                0                0               |
                {1} | 0 0   0   0   0   0   0   0                0                0               |
                {2} | 0 24  -29 -10 0   0   0   0                0                0               |
                {2} | 0 -36 19  -29 0   0   0   0                0                0               |
                {2} | 0 -30 19  -8  0   0   0   0                0                0               |
                {2} | 0 0   0   0   24  -29 -10 0                0                0               |
                {2} | 0 0   0   0   -36 19  -29 0                0                0               |
                {2} | 0 0   0   0   -30 19  -8  0                0                0               |
                {3} | 0 0   0   0   0   0   0   -22a-29b-24c-38d -16a+39b+21c+34d 19a-47b-39c-18d |

o5 : SimplicialModuleMap
i6 : g = randomSimplicialMap(D2, C)

          1               1
o6 = 0 : R  <----------- R  : 0
               | -13 |

          4                              4
     1 : R  <-------------------------- R  : 1
               {0} | -13 0   0   0  |
               {2} | 0   -43 -47 16 |
               {2} | 0   -15 38  22 |
               {2} | 0   -28 2   45 |

          9                                                                                           10
     2 : R  <--------------------------------------------------------------------------------------- R   : 2
               {0} | -13 0   0   0  0   0   0  0                0                0               |
               {2} | 0   -43 -47 16 0   0   0  0                0                0               |
               {2} | 0   -15 38  22 0   0   0  0                0                0               |
               {2} | 0   -28 2   45 0   0   0  0                0                0               |
               {2} | 0   0   0   0  -43 -47 16 0                0                0               |
               {2} | 0   0   0   0  -15 38  22 0                0                0               |
               {2} | 0   0   0   0  -28 2   45 0                0                0               |
               {3} | 0   0   0   0  0   0   0  -34a-48b-47c+47d -23a+39b+43c-17d 11a-38b+33c+40d |
               {3} | 0   0   0   0  0   0   0  19a-16b+7c+15d   -11a+48b+36c+35d 11a+46b-28c+d   |

o6 : SimplicialModuleMap
i7 : h = f||g

          4                   1
o7 = 0 : R  <--------------- R  : 0
               {1} | 0   |
               {1} | 0   |
               {1} | 0   |
               {0} | -13 |

          10                               4
     1 : R   <--------------------------- R  : 1
                {1} | 0   0   0   0   |
                {1} | 0   0   0   0   |
                {1} | 0   0   0   0   |
                {2} | 0   24  -29 -10 |
                {2} | 0   -36 19  -29 |
                {2} | 0   -30 19  -8  |
                {0} | -13 0   0   0   |
                {2} | 0   -43 -47 16  |
                {2} | 0   -15 38  22  |
                {2} | 0   -28 2   45  |

          19                                                                                             10
     2 : R   <----------------------------------------------------------------------------------------- R   : 2
                {1} | 0   0   0   0   0   0   0   0                0                0               |
                {1} | 0   0   0   0   0   0   0   0                0                0               |
                {1} | 0   0   0   0   0   0   0   0                0                0               |
                {2} | 0   24  -29 -10 0   0   0   0                0                0               |
                {2} | 0   -36 19  -29 0   0   0   0                0                0               |
                {2} | 0   -30 19  -8  0   0   0   0                0                0               |
                {2} | 0   0   0   0   24  -29 -10 0                0                0               |
                {2} | 0   0   0   0   -36 19  -29 0                0                0               |
                {2} | 0   0   0   0   -30 19  -8  0                0                0               |
                {3} | 0   0   0   0   0   0   0   -22a-29b-24c-38d -16a+39b+21c+34d 19a-47b-39c-18d |
                {0} | -13 0   0   0   0   0   0   0                0                0               |
                {2} | 0   -43 -47 16  0   0   0   0                0                0               |
                {2} | 0   -15 38  22  0   0   0   0                0                0               |
                {2} | 0   -28 2   45  0   0   0   0                0                0               |
                {2} | 0   0   0   0   -43 -47 16  0                0                0               |
                {2} | 0   0   0   0   -15 38  22  0                0                0               |
                {2} | 0   0   0   0   -28 2   45  0                0                0               |
                {3} | 0   0   0   0   0   0   0   -34a-48b-47c+47d -23a+39b+43c-17d 11a-38b+33c+40d |
                {3} | 0   0   0   0   0   0   0   19a-16b+7c+15d   -11a+48b+36c+35d 11a+46b-28c+d   |

o7 : SimplicialModuleMap
i8 : assert isWellDefined h
i9 : assert(target h === target f ++ target g)
i10 : assert(source h === source f)

See also

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.m2:2666:0.