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Macaulay2Doc :: Matrix ++ Matrix

Matrix ++ Matrix -- direct sum of maps

Synopsis

Description

f++g -- computes the direct sum of two maps between modules.

If an argument is a ring element or integer, it is promoted to a one by one matrix.

i1 : R = ZZ/101[a..c];
i2 : vars R ++ transpose vars R

o2 = {0}  | a b c 0 |
     {-1} | 0 0 0 a |
     {-1} | 0 0 0 b |
     {-1} | 0 0 0 c |

             4       4
o2 : Matrix R  <--- R
i3 : oo^[1]

o3 = {-1} | 0 0 0 a |
     {-1} | 0 0 0 b |
     {-1} | 0 0 0 c |

             3       4
o3 : Matrix R  <--- R
i4 : a++b++c

o4 = | a 0 0 |
     | 0 b 0 |
     | 0 0 c |

             3       3
o4 : Matrix R  <--- R
Selecting rows or columns of blocks:

See also