Abstract
Let F be an algebraically closed field and Mn be the n×n matrix algebra over F. A total graph of the full matrix algebra is the graph with Mn as vertices, and two distinct matrices A,B are adjacent if and only if A+B is singular. The characterization of all the automorphisms of the total graph is an open question. Motivated by this problem, we study pairs of maps on a subset of Mn preserving the singularity of matrix pencils A+λB. In particular, we characterize maps T1,T2:Mn→Mn satisfying the condition A+λB is singular if and only if T1(A)+λT2(B) is singular, for any A,B∈Mn and any non-zero λ∈F. Namely, we prove that in this case T1=T2 and they are of the form T1(A)=T2(A)=PAQ for all A∈Mn, or of the form T1(A)=T2(A)=PAtQ for all A∈Mn, where P,Q∈Mn are non-singular matrices.
| Original language | English |
|---|---|
| Pages (from-to) | 1-27 |
| Number of pages | 27 |
| Journal | Linear Algebra and Its Applications |
| Volume | 644 |
| DOIs | |
| State | Published - 1 Jul 2022 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2022 Elsevier Inc.
Funding
The work of the second author is financially supported by a scholarship of Theoretical Physics and Mathematics Advancement Foundation “ BASIS ” (grant No 21-8-3-18-1 ). The authors are grateful to Bojan Kuzma whose question inspired us to generalize our previous statements and proofs to a pair of maps, which led the main results of the paper. We also thank the anonymous referee for useful comments. The work of the second author is financially supported by a scholarship of Theoretical Physics and Mathematics Advancement Foundation “BASIS” (grant No 21-8-3-18-1).
| Funders | Funder number |
|---|---|
| Bojan Kuzma | |
| Foundation for the Advancement of Theoretical Physics and Mathematics | 21-8-3-18-1 |
Keywords
- Automorphisms of graphs
- Determinant
- Matrix pencils
- Preserver