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Feb 21, 2016 at 7:33 history edited Duchamp Gérard H. E. CC BY-SA 3.0
Improved formatting and spelling
Feb 21, 2016 at 6:42 history edited Duchamp Gérard H. E. CC BY-SA 3.0
added "A bit on the relation between right-left kernels-images"
Feb 21, 2016 at 6:36 history edited Duchamp Gérard H. E. CC BY-SA 3.0
added "A bit on the relation between right-left kernels-images"
Feb 20, 2016 at 22:04 history edited Duchamp Gérard H. E. CC BY-SA 3.0
Improved formatting and spelling
Feb 20, 2016 at 16:47 vote accept Drike
Feb 20, 2016 at 16:47
Feb 20, 2016 at 12:57 history edited Duchamp Gérard H. E. CC BY-SA 3.0
Added more hints and the explicit inverse of $M$
Feb 20, 2016 at 12:54 comment added Duchamp Gérard H. E. @SebastianGoette Of course, I had seen the ACL comments, but I wanted to give an explicit example.
Feb 20, 2016 at 12:50 history edited Duchamp Gérard H. E. CC BY-SA 3.0
Added more hints and the explicit inverse of $M$
Feb 20, 2016 at 12:28 comment added Duchamp Gérard H. E. No, do not be confused because this does not invalidate your arguments and my warning is just to prevent people to treat lightheartedly rank notions. I'll put more hints in my answer.
Feb 20, 2016 at 11:08 comment added Sebastian Goette I am confused now. Why would you consider columns as a left vector space at all? I also don't think that the arguments in my answer below fail for your matrix, call it $A$. The image of $A$ acting from the right on row vectors is spanned by the rows viewed as a left vector space, and they are linearly independent, so the row rank is 2. The image of $A$ acting on columns from the left is spanned by the columns, viewed as a right vector space, and has dimension 2 again. If you transpose the matrix, both ranks become 1. So we learn that transposition is dangerous, see @ACL s comment on my answer.
Feb 20, 2016 at 9:13 history edited Duchamp Gérard H. E. CC BY-SA 3.0
Improved the aesthetics of the example
Feb 20, 2016 at 8:16 history edited Duchamp Gérard H. E. CC BY-SA 3.0
Added a warning about the rank (this question is very interesting)
Feb 18, 2016 at 18:09 history edited Duchamp Gérard H. E. CC BY-SA 3.0
improved the answer
Feb 18, 2016 at 17:44 history answered Duchamp Gérard H. E. CC BY-SA 3.0