Letter to the Editor

Letter to the Editor Reliable Computing (2006) 12: 245–246 DOI: 10.1007/s11155-006-7222-7  c Springer 2006 ˇ ´ JIRIROHN Institute of Computer Science, Czech Academy of Sciences, Pod vodar ´ enskou ve ˇzˇ´ı 2, 182 07 Prague, Czech Republic, e-mail: rohn@cs.cas.cz (Received: 25 October 2005) E. Hansen has recently published in [2] a criterion for regularity of interval matrices. As is well known, an n × n interval matrix A =[A, A]is called regular if each A ∈ A is nonsingular. Hansen first defines vertex matrices in A as matrices satisfying A ∈ {A , A } (i, j =1,…, n). (1) ij ij ij His result is then formulated as follows: An interval matrix A is regular if and only if the determinants of all the vertex matrices in A are nonzero and of the same sign. If A < A, then according to (1) for each i, j we have two options for choosing A , ij hence there are 2 mutually different vertex matrices in this case. So, in the worst case Hansen’s criterion requires evaluation of determinants of 2 matrices. This result, however, brings nothing new and is in fact much worse than a criteri- on published more than 20 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Reliable Computing Springer Journals

Letter to the Editor

Loading next page...
Kluwer Academic Publishers
Copyright © 2006 by Springer Science + Business Media, Inc.
Mathematics; Numeric Computing; Approximations and Expansions; Computational Mathematics and Numerical Analysis; Mathematical Modeling and Industrial Mathematics
Publisher site
See Article on Publisher Site


You’re reading a free preview. Subscribe to read the entire article.

DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

Monthly Plan

  • Read unlimited articles
  • Personalized recommendations
  • No expiration
  • Print 20 pages per month
  • 20% off on PDF purchases
  • Organize your research
  • Get updates on your journals and topic searches


Start Free Trial

14-day Free Trial

Best Deal — 39% off

Annual Plan

  • All the features of the Professional Plan, but for 39% off!
  • Billed annually
  • No expiration
  • For the normal price of 10 articles elsewhere, you get one full year of unlimited access to articles.



billed annually
Start Free Trial

14-day Free Trial