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Macaulay2Doc :: id

id -- identity map

Synopsis

Description

i1 : R = QQ[a..d];
i2 : id_R

o2 = map(R,R,{a, b, c, d})

o2 : RingMap R <--- R
i3 : id_(R^3)

o3 = | 1 0 0 |
     | 0 1 0 |
     | 0 0 1 |

             3       3
o3 : Matrix R  <--- R
i4 : C = res coker vars R

      1      4      6      4      1
o4 = R  <-- R  <-- R  <-- R  <-- R  <-- 0
                                         
     0      1      2      3      4      5

o4 : ChainComplex
i5 : id_C

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

          4                       4
     1 : R  <------------------- R  : 1
               {1} | 1 0 0 0 |
               {1} | 0 1 0 0 |
               {1} | 0 0 1 0 |
               {1} | 0 0 0 1 |

          6                           6
     2 : R  <----------------------- R  : 2
               {2} | 1 0 0 0 0 0 |
               {2} | 0 1 0 0 0 0 |
               {2} | 0 0 1 0 0 0 |
               {2} | 0 0 0 1 0 0 |
               {2} | 0 0 0 0 1 0 |
               {2} | 0 0 0 0 0 1 |

          4                       4
     3 : R  <------------------- R  : 3
               {3} | 1 0 0 0 |
               {3} | 0 1 0 0 |
               {3} | 0 0 1 0 |
               {3} | 0 0 0 1 |

          1                 1
     4 : R  <------------- R  : 4
               {4} | 1 |

     5 : 0 <----- 0 : 5
              0

o5 : ChainComplexMap

Ways to use id :

For the programmer

The object id is a scripted functor.