Matrix inversion

Thread View: fj.mail-lists.reduce

1 messages

[T] Back to Threads [V] Tree View [G] Group Articles

1 total messages Started by Carlos Ruiz de Velasco Tue, 08 Sep 1992 16:28

#10

Author: Carlos Ruiz de Velasco
Date: Tue, 08 Sep 1992 16:28

57 lines
1294 bytes

I have found the following problem working with matrix inversion
in positive characteristic:

REDUCE 3.4, 15-Jul-91 ...

1: on modular;setmod 12;

1

3: a:=mat((6,1),(5,0));
     [6  1]
A := [    ]
     [5  0]


4: b:=a**(-1);
     [0  7]
B := [    ]
     [1  6]


5: a*b;
[1  0 ]
[     ]
[0  11]


6: off modular;
7: c:=a**(-1);
     [     1   ]
     [0   ---  ]
     [     5   ]
C := [         ]
     [     - 6 ]
     [1  ------]
     [     5   ]


8: on modular;
9: d:=c;
     [0  5]
D := [    ]
     [1  6]


10: a*d;
[1  0]
[    ]
[0  1]


11: bye;

Clearly, matrix A is regular in M2x2(Z/12) and A**(-1) is D in that ring.
What happens?
Best regards
             Carlos Ruiz de Velasco

Thread Navigation

This is a paginated view of messages in the thread with full content displayed inline.

Messages are displayed in chronological order, with the original post highlighted in green.

Use pagination controls to navigate through all messages in large threads.

Back to All Threads