| Title: | A note on ultrametric matrices (English) | 
| Author: | Zhang, Xiao-Dong | 
| Language: | English | 
| Journal: | Czechoslovak Mathematical Journal | 
| ISSN: | 0011-4642 (print) | 
| ISSN: | 1572-9141 (online) | 
| Volume: | 54 | 
| Issue: | 4 | 
| Year: | 2004 | 
| Pages: | 929-940 | 
| Summary lang: | English | 
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| Category: | math | 
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| Summary: | It is proved in this paper that special generalized ultrametric and special  $\mathcal U$  matrices are, in a sense, extremal matrices in the boundary of the set of generalized ultrametric and $ \mathcal U$ matrices, respectively. Moreover, we present a new class of inverse $M$-matrices which generalizes the class of  $\mathcal U$ matrices. (English) | 
| Keyword: | generalized ultrametric matrix | 
| Keyword: | $ \mathcal U$ matrix | 
| Keyword: | weighted graph | 
| Keyword: | inverse $M$-matrix | 
| MSC: | 05C50 | 
| MSC: | 15A09 | 
| MSC: | 15A48 | 
| MSC: | 15A57 | 
| idZBL: | Zbl 1080.15500 | 
| idMR: | MR2100005 | 
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| Date available: | 2009-09-24T11:18:59Z | 
| Last updated: | 2020-07-03 | 
| Stable URL: | http://hdl.handle.net/10338.dmlcz/127941 | 
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