Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Let $(a_{ij}), i,j \in \{1,...,n\}$ be a matrix. What are the names for the following special square submatrices:

  • for any set of indices $J⊂{1,2,..,n}$, the submatrix $(a_{jk})j,k\in J$,
  • a submatrix formed by removing the last m rows and last m columns;
  • a submatrix formed by removing any m rows and any m columns.

Does a principal submatrice mean any of the above three kinds? Thanks!

share|cite|improve this question
up vote 2 down vote accepted

The first kind is a principal submatrix, the second kind is a leading principal submatrix, and the last kind is just any old submatrix. :-)

share|cite|improve this answer
Thanks! Why do you call the last one "old"? – Tim Sep 30 '12 at 18:49
It's just an idiom, not a mathematical definition. – Hans Lundmark Sep 30 '12 at 18:49

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.