Kokol Bukovšek, Damjana; Laffey, Thomas; Šmigoc, Helena Completely positive factorizations associated with Euclidean distance matrices corresponding to an arithmetic progression. (English) Zbl 1437.15045 Linear Algebra Appl. 597, 113-132 (2020). Reviewer: Erich W. Ellers (Toronto) MSC: 15B48 15A23 15B36 PDFBibTeX XMLCite \textit{D. Kokol Bukovšek} et al., Linear Algebra Appl. 597, 113--132 (2020; Zbl 1437.15045) Full Text: DOI arXiv
Laffey, Thomas; Šmigoc, Helena The integer cp-rank of \(2 \times 2\) matrices. (English) Zbl 1433.15033 Spec. Matrices 7, 272-275 (2019). MSC: 15B36 15B48 PDFBibTeX XMLCite \textit{T. Laffey} and \textit{H. Šmigoc}, Spec. Matrices 7, 272--275 (2019; Zbl 1433.15033) Full Text: DOI arXiv
Laffey, Thomas J.; Šmigoc, Helena Integer completely positive matrices of order two. (English) Zbl 1474.15082 Pure Appl. Funct. Anal. 3, No. 4, 633-638 (2018). MSC: 15B36 15A23 15B48 PDFBibTeX XMLCite \textit{T. J. Laffey} and \textit{H. Šmigoc}, Pure Appl. Funct. Anal. 3, No. 4, 633--638 (2018; Zbl 1474.15082) Full Text: arXiv Link
Laffey, Thomas J.; Šmigoc, Helena Diagonal realizability in the nonnegative inverse eigenvalue problem. (English) Zbl 1474.15046 Pure Appl. Funct. Anal. 3, No. 4, 625-631 (2018). MSC: 15A29 15A20 15B48 PDFBibTeX XMLCite \textit{T. J. Laffey} and \textit{H. Šmigoc}, Pure Appl. Funct. Anal. 3, No. 4, 625--631 (2018; Zbl 1474.15046) Full Text: arXiv Link
Laffey, Thomas J.; Loewy, Raphael; Šmigoc, Helena Power series with positive coefficients arising from the characteristic polynomials of positive matrices. (English) Zbl 1345.15011 Math. Ann. 364, No. 1-2, 687-707 (2016). Reviewer: Alexander Kovačec (Coimbra); Frank Uhlig (Auburn) MSC: 15B48 15A29 15A18 30B10 37B10 PDFBibTeX XMLCite \textit{T. J. Laffey} et al., Math. Ann. 364, No. 1--2, 687--707 (2016; Zbl 1345.15011) Full Text: DOI arXiv
Laffey, Thomas J. Formal power series and the spectra of nonnegative real matrices. (English) Zbl 1296.15006 Math. Proc. R. Ir. Acad. 113A, No. 2, 97-106 (2013). Reviewer: Mihail Voicu (Iaşi) MSC: 15A18 15A29 15A42 15B48 PDFBibTeX XMLCite \textit{T. J. Laffey}, Math. Proc. R. Ir. Acad. 113A, No. 2, 97--106 (2013; Zbl 1296.15006) Full Text: DOI
Laffey, Thomas J. A constructive version of the Boyle-Handelman theorem on the spectra of nonnegative matrices. (English) Zbl 1241.15007 Linear Algebra Appl. 436, No. 6, 1701-1709 (2012). Reviewer: Süleyman Güler (Aydin) MSC: 15A18 15A29 15A42 15B36 15B48 PDFBibTeX XMLCite \textit{T. J. Laffey}, Linear Algebra Appl. 436, No. 6, 1701--1709 (2012; Zbl 1241.15007) Full Text: DOI arXiv
Laffey, Thomas J.; Šmigoc, Helena Nonnegatively realizable spectra with two positive eigenvalues. (English) Zbl 1205.15019 Linear Multilinear Algebra 58, No. 7-8, 1053-1069 (2010). Reviewer: Valeriu Prepeliţă (Bucureşti) MSC: 15A18 15A29 15B48 PDFBibTeX XMLCite \textit{T. J. Laffey} and \textit{H. Šmigoc}, Linear Multilinear Algebra 58, No. 7--8, 1053--1069 (2010; Zbl 1205.15019) Full Text: DOI
Semigroups Working Group at LAW’08 [Radjavi, Hejdar; Drnovšek, Roman; Bernik, Janez; Cigler, Grega; Jafarian, Ali A.; Bukovšek, Damjana Kokol; Košir, Tomaž; Fijavž, Marjeta Kramar; Kudryavtseva, Ganna; Laffey, Thomas; Livshits, Leo; MacDonald; Gordon W. Omladič, Matjaž; Rosenthal, Peter] Semigroups of operators with nonnegative diagonals. (English) Zbl 1202.47049 Linear Algebra Appl. 433, No. 11-12, 2080-2087 (2010). MSC: 47D03 15B48 47A15 47B34 PDFBibTeX XMLCite \textit{Semigroups Working Group at LAW'08}, Linear Algebra Appl. 433, No. 11--12, 2080--2087 (2010; Zbl 1202.47049) Full Text: DOI
Laffey, Thomas J.; Loewy, Raphael; Šmigoc, Helena Nonnegative matrices that are similar to positive matrices. (English) Zbl 1190.15036 SIAM J. Matrix Anal. Appl. 31, No. 2, 629-649 (2009). Reviewer: Grozio Stanilov (Sofia) MSC: 15B48 15A04 PDFBibTeX XMLCite \textit{T. J. Laffey} et al., SIAM J. Matrix Anal. Appl. 31, No. 2, 629--649 (2009; Zbl 1190.15036) Full Text: DOI
Laffey, Thomas J.; Šmigoc, Helena On a classic example in the nonnegative inverse eigenvalue problem. (English) Zbl 1149.15008 Electron. J. Linear Algebra 17, 333-342 (2008). Reviewer: C. M. da Fonseca (Coimbra) MSC: 15A18 15B48 15A29 PDFBibTeX XMLCite \textit{T. J. Laffey} and \textit{H. Šmigoc}, Electron. J. Linear Algebra 17, 333--342 (2008; Zbl 1149.15008) Full Text: DOI EuDML EMIS Link
Laffey, Thomas J.; Šmigoc, Helena Spectra of principal submatrices of nonnegative matrices. (English) Zbl 1130.15006 Linear Algebra Appl. 428, No. 1, 230-238 (2008). Reviewer: C. M. da Fonseca (Coimbra) MSC: 15A18 15B48 15A29 PDFBibTeX XMLCite \textit{T. J. Laffey} and \textit{H. Šmigoc}, Linear Algebra Appl. 428, No. 1, 230--238 (2008; Zbl 1130.15006) Full Text: DOI
Laffey, Thomas J.; Šmigoc, Helena Construction of nonnegative symmetric matrices with given spectrum. (English) Zbl 1116.15012 Linear Algebra Appl. 421, No. 1, 97-109 (2007). Reviewer: Frank Uhlig (Auburn) MSC: 15A29 15A18 15B48 15B57 PDFBibTeX XMLCite \textit{T. J. Laffey} and \textit{H. Šmigoc}, Linear Algebra Appl. 421, No. 1, 97--109 (2007; Zbl 1116.15012) Full Text: DOI
Laffey, Thomas; Šmigoc, Helena Structured matrices in the nonnegative inverse eigenvalue problem. (English) Zbl 1180.15009 Azenhas, Olga (ed.) et al., Mathematical papers in honour of Eduardo Marques de Sá on the occasion of his 60th birthday. Coimbra: Universidade de Coimbra, Departamento de Matemática (ISBN 978-972-8564-43-8/pbk). Textos de Matemática. Série B 39, 93-106 (2006). MSC: 15A18 15A29 15B48 PDFBibTeX XMLCite \textit{T. Laffey} and \textit{H. Šmigoc}, Textos Mat., Sér. B 39, 93--106 (2006; Zbl 1180.15009)
Laffey, Thomas J.; Šmigoc, Helena Nonnegative realization of spectra having negative real parts. (English) Zbl 1103.15005 Linear Algebra Appl. 416, No. 1, 148-159 (2006). Reviewer: Ralf Gramlich (Darmstadt) MSC: 15A18 15A29 15B48 PDFBibTeX XMLCite \textit{T. J. Laffey} and \textit{H. Šmigoc}, Linear Algebra Appl. 416, No. 1, 148--159 (2006; Zbl 1103.15005) Full Text: DOI
Laffey, Thomas J. Perturbing non-real eigenvalues of nonnegative real matrices. (English) Zbl 1099.15007 Electron. J. Linear Algebra 12, 73-76 (2004/2005). Reviewer: Alan L. Andrew (Bundoora) MSC: 15A18 15A29 15B48 PDFBibTeX XMLCite \textit{T. J. Laffey}, Electron. J. Linear Algebra 12, 73--76 (2004; Zbl 1099.15007) Full Text: EuDML EMIS
Laffey, Thomas J. Extreme nonnegative matrices. (English) Zbl 0933.15028 Linear Algebra Appl. 275-276, 349-357 (1998). MSC: 15A29 15A18 15B48 PDFBibTeX XMLCite \textit{T. J. Laffey}, Linear Algebra Appl. 275--276, 349--357 (1998; Zbl 0933.15028) Full Text: DOI
Laffey, Thomas J.; Meehan, Eleanor A refinement of an inequality of Johnson, Loewy and London on nonnegative matrices and some applications. (English) Zbl 0907.15013 Electron. J. Linear Algebra 3, 119-128 (1998). Reviewer: J.M.Day (San José) MSC: 15A45 15B48 15A18 05C50 PDFBibTeX XMLCite \textit{T. J. Laffey} and \textit{E. Meehan}, Electron. J. Linear Algebra 3, 119--128 (1998; Zbl 0907.15013) Full Text: DOI EuDML EMIS
Laffey, Thomas J. A sparsity result on nonnegative real matrices with given spectrum. (English) Zbl 0877.15025 Janas, Jan (ed.) et al., Linear operators. Proceedings of the semester organized at the Stefan Banach International Mathematical Center, Warsaw, Poland, February 7–May 15, 1994. Warsaw: Polish Academy of Sciences, Inst. of Mathematics, Banach Cent. Publ. 38, 187-191 (1997). MSC: 15B48 15A18 PDFBibTeX XMLCite \textit{T. J. Laffey}, Banach Cent. Publ. 38, 187--191 (1997; Zbl 0877.15025) Full Text: EuDML
Johnson, Charles R.; Laffey, Thomas J.; Loewy, Raphael The real and the symmetric nonnegative inverse eigenvalue problems are different. (English) Zbl 0861.15007 Proc. Am. Math. Soc. 124, No. 12, 3647-3651 (1996). MSC: 15A18 15B48 PDFBibTeX XMLCite \textit{C. R. Johnson} et al., Proc. Am. Math. Soc. 124, No. 12, 3647--3651 (1996; Zbl 0861.15007) Full Text: DOI
Hannah, John; Laffey, Thomas J. Nonnegative factorization of completely positive matrices. (English) Zbl 0519.15007 Linear Algebra Appl. 55, 1-9 (1983). MSC: 15B48 15A23 15A63 PDFBibTeX XMLCite \textit{J. Hannah} and \textit{T. J. Laffey}, Linear Algebra Appl. 55, 1--9 (1983; Zbl 0519.15007) Full Text: DOI