Skip to content
BY 4.0 license Open Access Published by De Gruyter Open Access July 9, 2021

Determinantal inequalities of Hua-Marcus-Zhang type for quaternion matrices

  • Yan Hong ORCID logo and Feng Qi ORCID logo EMAIL logo
From the journal Open Mathematics

Abstract

In this paper, the authors extend determinantal inequalities of the Hua-Marcus-Zhang type for positive definite matrices to the corresponding ones for quaternion matrices.

MSC 2010: 15B33; 11R52; 15A42; 15A45; 16H05; 20G20

1 Introduction and motivations

In 1955, Hua [1,2] established an elegant determinantal inequality as follows.

Theorem 1.1

[1,2, Theorems 1 and 2] Let A , B C n × n and A , B be conjugate matrices of A , B . If I n A A and I n B B are positive definite, then

(1.1) det ( I n A A ) det ( I n B B ) + det ( A B ) 2 det ( I n A B ) 2 ,

where I n denotes identity matrix of n order. In particular,

det ( I n A A ) det ( I n B B ) det ( I n A B ) 2 .

For A C n × n , we denote its eigenvalues and singular values by

λ 1 ( A ) , λ 2 ( A ) , , λ n ( A ) and σ 1 ( A ) , σ 2 ( A ) , , σ n ( A ) ,

respectively. If all eigenvalues of A C n × n are real, we assume

(1.2) λ 1 ( A ) λ 2 ( A ) λ n ( A ) ,

while we always write

(1.3) σ 1 ( A ) σ 2 ( A ) σ n ( A ) .

In 1958, Marcus [3] extended the determinantal inequality (1.1) to the following family of inequalities for eigenvalues of matrices.

Theorem 1.2

[3, Theorem] Let A , B C n × n . If I n A A and I n B B are positive definite, then inequality

(1.4) j = 1 k σ n j + 1 2 ( I n A B ) j = 1 k ( 1 λ j ( A A ) ) ( 1 λ j ( B B ) ) ,

is valid for 1 k n .

In 2011, Zhang [4] found a reversion of the determinantal inequality (1.1) below.

Theorem 1.3

[4, Theorem 7.18] If A , B C n × n , then

(1.5) det ( I n A B ) 2 det ( I n + A A ) det ( I n + B B ) det ( A + B ) 2 .

In the past few decades, many kinds of determinantal inequalities of the Hua-Marcus-Zhang type were presented in [3,4, 5,6,7, 8,9] and closely related references therein. In recent years, quaternions have been widely used in system control, signal and color image processing, geometric rotation, quantum mechanics, algebra, analysis, and other fields. For details, please refer to previous studies [10,11, 12,13,14, 15,16].

In this paper, we adopt notations for quaternion matrices in our own paper [17]. Hamilton [18] introduced the concept of real quaternions by

H = { x = a + b i + c j + d k : a , b , c , d R and i , j , k R } ,

where there exist the following operations:

i ¯ = i , j ¯ = j , k ¯ = k , i 2 = k 2 = j 2 = 1 , ij = ji = k , jk = kj = i , ki = ik = j .

Let H n × m be the set of n × m quaternion matrices and let H n be the set of self-conjugate n × n quaternion matrices. Xie [19,20, 21,22] studied a similarity standard form of the body matrices, the eigenvalue theory of centralizable matrices, and the determinant theory of self-conjugate quaternion matrices. Zhuang [23] established the Cauchy interleaving theorem of eigenvalues of self-conjugate quaternion matrices. Cao [24] investigated inequalities between eigenvalues and singular values of products of two quaternion matrices. The papers [17,25,26, 27,28,29, 30,31] are also related to the topic of this paper. The research of quaternion matrices has been being continuously active.

Definition 1.1

[32] Let A H n × n . If there exists λ H and x H n { 0 } such that

A x = λ x ( A x = x λ ) ,

then we say that λ and x are the left (right) eigenvalue and the corresponding left (right) eigenvector of A , respectively.

Since the quaternions do not commute, it is mandatory to treat the linear systems A x = λ x and A x = x λ separately. Rewrite the first one as ( λ I A ) x = 0 . In the complex case, the fact that det ( λ I A ) = 0 has a solution guarantees an eigenvalue for A . The existence of eigenvalue of a quaternion matrix is much more complicated, see [32]. It is known [33,34] that the right spectrum is always nonempty. In [35], Wood used a topological method to confirm that the left eigenvalue always exists.

Over a long period of time, there have been various kinds of definitions of determinant over the quaternion, see [19,22,36, 37,38]. Since eigenvalues of self-conjugate quaternion matrices are real numbers, see Lemma 2.1, we use the definition of determinants in [21,22] to investigate our problems in this paper.

In what follows, we assume that the eigenvalues λ j ( A ) of A H n and the singular values σ j ( A ) of A H n × n are expressed in the orders (1.2) and (1.3), respectively. In this paper, we will extend inequalities (1.1), (1.4), and (1.5) to the corresponding ones for quaternion matrices.

2 Lemmas

In order to extend inequalities (1.1), (1.4), and (1.5) to the corresponding ones for quaternion matrices, we need the following lemmas.

Lemma 2.1

[17, Proposition 2.1], [21, Theorem 13], and [22, Theorem 3] For A H n , there exists a generalized unitary matrix U H n × n (that is, U U = U U = I n ) such that

U A U = diag ( λ 1 ( A ) , λ 2 ( A ) , , λ n ( A ) ) .

Furthermore, if A is positive definite, then the least eigenvalue λ n ( A ) is positive.

Lemma 2.2

[17, Proposition 2.2] and [24, Theorems 2 and 3] Suppose A , B H n and B is positive definite. Then

  1. there exists a nonsingular matrix P = ( p 1 , p 2 , , p n ) H n × n such that

    P B P = I n and P A P = diag ( λ 1 ( A ) , λ 2 ( A ) , , λ n ( A ) ) ;

  2. the products A B and B A are both centralizable matrices and both of them are similar to a real diagonal matrix.

Lemma 2.3

Let A , B H n . If A , B are both positive semidefinite, then

(2.1) det ( A + B ) det ( A ) + det ( B ) .

Proof

When det B = 0 , inequality (2.1) holds trivially.

When det B 0 , by Lemma 2.2, there exists a nonsingular matrix P H n × n such that

P 1 ( A + B ) P = ( P P ) 1 ( D + I n ) ,

where D = diag ( λ 1 ( A + B ) , λ 2 ( A + B ) , , λ n ( A + B ) ) . Since

det ( A ) = [ det ( P P ) ] 1 det ( D ) , det ( B ) = [ det ( P P ) ] 1 , det ( D + I n ) det ( D ) + 1 ,

using Lemma 2.2, it follows that

det ( A + B ) = [ det ( P P ) ] 1 det ( D + I n ) det ( A ) + det ( B ) .

The proof of Lemma 2.3 is complete.□

Lemma 2.4

[23, Theorem 1] Let A H n be a matrix partitioned as

A = A k 1 A k 2 A k 3 A k 4 , A k 1 H k , 1 k n .

Then

λ ( A ) λ n k + ( A k 1 ) λ n k + ( A )

for 1 k , n . In particular, if A is positive semidefinite, then

(2.2) = 1 k λ ( A ) det ( A k 1 ) = 1 k λ n + 1 ( A )

for 1 k n .

Lemma 2.5

Let A , B H n × n . For 1 k n , we have

(2.3) = 1 k σ ( A ) σ ( B ) = 1 k σ ( A B ) = 1 k σ ( A ) σ n + 1 ( B )

(2.4) = 1 k σ n + 1 ( A B ) = 1 k σ n + 1 ( A ) σ n + 1 ( B ) .

Proof

The first inequality (2.3) in Lemma 2.5 comes from [39, Theorem 3].

We assume that A and B are nonsingular, otherwise we use the continuity of A A + ε I n and B B + ε I n in ε > 0 . By inequality (2.3), we obtain

= 1 k σ n + 1 ( A 1 ) σ ( B 1 ) = 1 k σ ( ( A B ) 1 ) = 1 k σ ( A 1 ) σ ( B 1 ) .

Since σ ( A 1 ) = σ n + 1 1 ( A ) for 1 n , we readily see that inequality (2.4) holds. The proof of Lemma 2.5 is complete.□

Lemma 2.6

Let A , B H n × n . Then

(2.5) I n + A A = ( A + B ) ( I n + B B ) 1 ( A + B ) + ( I n A B ) ( I n + B B ) 1 ( I n A B ) .

If I n A A and I n B B are nonsingular, then

(2.6) ( I n B A ) ( I n A A ) 1 ( I n A B ) = ( I n B B ) + ( A B ) ( I n A A ) 1 ( A B ) .

Proof

This follows from arguments similar to those corresponding ones in [4, p. 229] and [7, p. 124].□

3 Determinantal inequalities for quaternion matrices

We are now in a position to state and prove our main results which extend inequalities (1.1), (1.4), and (1.5) to the corresponding ones for quaternion matrices.

Theorem 3.1

Let A , B H n × n . If I n A A and I n B B are both positive definite, then

(3.1) j = 1 k σ n j + 1 2 ( I n A B ) j = 1 k [ 1 λ j ( A A ) ] [ 1 λ j ( B B ) ] + j = 1 k [ 1 λ j ( A A ) ] [ 1 λ n j + 1 ( A A ) ] 1 σ n j + 1 2 ( A B )

for 1 k n .

Proof

Since ( I n A B ) ( I n A B ) is positive semidefinite, by Lemma 2.1, there exists a generalized unitary matrix U = ( u 1 , u 2 , , u n ) H n × n such that

(3.2) U ( I n A B ) ( I n A B ) U = diag ( σ 1 2 ( I n A B ) , σ 2 2 ( I n A B ) , , σ n 2 ( I n A B ) ) .

Putting U k = ( u n k + 1 , , u n ) H n × k , by identity (2.6) in Lemma 2.6, we obtain

(3.3) U k ( I n B A ) ( I n A A ) 1 ( I n A B ) U k = U k ( I n B B ) U k + U k ( A B ) ( I n A A ) 1 ( A B ) U k .

Taking determinants on both sides of (3.3) and using Lemma 2.3, we acquire

det ( U k ( I n B A ) ( I n A A ) 1 ( I n A B ) U k ) = det ( U k ( I n B B ) U k + U k ( A B ) ( I n A A ) 1 ( A B ) U k ) det ( U k ( I n B B ) U k ) + det ( U k ( A B ) ( I n A A ) 1 ( A B ) U k ) .

Applying inequalities (2.2) and (2.4) yields

det ( U k ( I n B B ) U k ) j = 1 k λ n j + 1 ( I n B B ) = j = 1 k [ 1 λ j ( B B ) ]

and

det ( U k ( A B ) ( I n A A ) 1 ( A B ) U k ) j = 1 k σ n j + 1 2 ( ( A B ) ( I n A A ) 1 ( A B ) ) j = 1 k σ n j + 1 2 ( A B ) λ n j + 1 ( ( I n A A ) 1 ) = j = 1 k σ n j + 1 2 ( A B ) [ 1 λ n j + 1 ( A A ) ] 1 .

Using Lemma 2.4, inequality (2.3), and the matrix decomposition (3.2), we arrive at

det ( U k ( I n B A ) ( I n A A ) 1 ( I n A B ) U k ) = j = 1 k λ j ( U k ( I n B A ) ( I n A A ) 1 ( I n A B ) U k ) j = 1 k σ j 2 ( ( I n A B ) U k ) λ j ( ( I n A A ) 1 ) = j = 1 k σ n j + 1 2 ( I n A B ) [ 1 λ j ( A A ) ] 1 .

The proof of Theorem 3.1 is complete.□

Corollary 3.1

Let A , B H n × n . If I n A A and I n B B are both positive definite, then

j = 1 k σ n j + 1 2 ( I n A B ) j = 1 k [ 1 λ j ( A A ) ] [ 1 λ j ( B B ) ]

for 1 k n .

Proof

This follows from inequality (3.1) in Theorem 3.1.□

Corollary 3.2

Let A , B H n × n . If I n A A and I n B B are both positive definite, then

det ( I n A A ) det ( I n B B ) + det ( A B ) 2 det ( I n A B ) 2 .

In particular,

det ( I n A A ) det ( I n B B ) det ( I n A B ) 2 .

Proof

This follows from letting k = n in Theorem 3.1.□

Theorem 3.2

Let A , B H n × n . For 1 k n , we have

j = 1 k σ n j + 1 2 ( I n A B ) + j = 1 k σ n j + 1 2 ( A + B ) j = 1 k [ 1 + λ n j + 1 ( A A ) ] [ 1 + λ j ( B B ) ] .

Proof

There exists a generalized unitary matrix U = ( u 1 , u 2 , , u n ) H n × n such that

U ( I n + A A ) U = diag ( λ 1 ( I n + A A ) , λ 2 ( I n + A A ) , , λ n ( I n + A A ) ) .

Taking U k = ( u n k + 1 , , u n ) H n × k , utilizing the matrix identity (2.5) in Lemma 2.6, and employing inequalities in Lemmas 2.3 and 2.4 lead to

j = 1 k [ 1 + λ n j + 1 ( A A ) ] = det ( U k ( I n + A A ) U k ) det ( U k ( A + B ) ( I n + B B ) 1 ( A + B ) U k ) + det ( U k ( I n A B ) ( I n + B B ) 1 ( I n A B ) U k ) j = 1 k σ n j + 1 2 ( A + B ) [ 1 + λ j ( B B ) ] 1 + j = 1 k σ n j + 1 2 ( I n A B ) [ 1 + λ j ( B B ) ] 1 .

The proof of Theorem 3.2 is thus complete.□

Corollary 3.3

Let A , B H n × n . Then

det ( I n A B ) 2 det ( I n + A A ) det ( I n + B B ) det ( A + B ) 2 .

Proof

This follows from setting k = n in Theorem 3.2.□


https://qifeng618.wordpress.com

# Dedicated to Professor Jen-Chih Yao at China Medical University in Taiwan.


Acknowledgements

The authors appreciate anonymous referees for their careful corrections to and valuable comments on the original version of this paper.

  1. Funding information: This work was supported in part by the Natural Science Foundation of Inner Mongolia (Grant No. 2019MS01007), by the Science Research Fund of Inner Mongolia University for Nationalities (Grant No. NMDBY15019), and by the Research Program of Science and Technology at Universities of Inner Mongolia Autonomous Region (Grant No. NJZY19157 and No. NJZY20119) in China.

  2. Author contributions: All authors contributed equally to the manuscript and read and approved the final manuscript.

  3. Conflict of interest: Authors state no conflict of interest.

  4. Data availability statement: Data sharing is not applicable to this article as no new data were created or analyzed in this study.

References

[1] L.-K. Hua , Inequalities involving determinants, Acta Math. Sinica 5 (1955), 463–470. (Chinese) Search in Google Scholar

[2] L.-K. Hua , Inequalities involving determinants, Transl. Amer. Math. Soc. Ser. II 32 (1963), 265–272, http://www.ams.org/books/trans2/032/11. 10.1090/trans2/032/11Search in Google Scholar

[3] M. Marcus , On a determinantal inequality, Amer. Math. Monthly 65 (1958), no. 4, 266–268, https://doi.org/10.2307/2310245 . 10.2307/2310245Search in Google Scholar

[4] F. Zhang , Matrix Theory: Basic Results and Techniques, 2nd ed., Universitext, Springer, New York, 2011, https://doi.org/10.1007/978-1-4614-1099-7 . 10.1007/978-1-4614-1099-7Search in Google Scholar

[5] T. Ando , Positivity of operator-matrices of Hua-type, Banach J. Math. Anal. 2 (2008), no. 2, 1–8, https://doi.org/10.15352/bjma/1240336286 . 10.15352/bjma/1240336286Search in Google Scholar

[6] A. W. Marshall , I. Olkin , and B. C. Arnold , Inequalities: Theory of Majorization and its Applications, 2nd ed., Springer Verlag, New York-Dordrecht-Heidelberg-London, 2011, http://dx.doi.org/10.1007/978-0-387-68276-1. Search in Google Scholar

[7] C. C. Paige , G. P. H. Styan , B.-Y. Wang , and F. Zhang , Hua’s matrix equality and Schur complements, Int. J. Inf. Syst. Sci. 4 (2008), no. 1, 124–135. Search in Google Scholar

[8] C. Xu , Z. Xu , and F. Zhang , Revisiting Hua-Marcus-Bellman-Ando inequalities on contractive matrices, Linear Algebra Appl. 430 (2009), no. 5–6, 1499–1508, https://doi.org/10.1016/j.laa.2007.11.011 . 10.1016/j.laa.2007.11.011Search in Google Scholar

[9] G. Xu , C. Xu , and F. Zhang , Contractive matrices of Hua type, Linear Multilinear Algebra 59 (2011), no. 2, 159–172, https://doi.org/10.1080/03081080903266888 . 10.1080/03081080903266888Search in Google Scholar

[10] S. L. Adler , Quaternionic Quantum Mechanics and Quantum Fields, International Series of Monographs on Physics, vol. 88 , The Clarendon Press, Oxford University Press, New York, 1995. Search in Google Scholar

[11] D. Finkelstein , J. M. Jauch , S. Schiminovich , and D. Speiser , Foundations of quaternion quantum mechanics, J. Mathematical Phys. 3 (1962), 207–220, https://doi.org/10.1063/1.1703794 . 10.1063/1.1703794Search in Google Scholar

[12] J. B. Kuipers , Quaternions and Rotation Sequences: A Primer with Applications to Orbits, Aerospace, and Virtual Reality, Princeton University Press, Princeton, NJ, 1999. 10.1515/9780691211701Search in Google Scholar

[13] J. P. Morais , S. Georgiev , and W. Sprößig , Real Quaternionic Calculus Handbook, Birkhäuser/Springer, Basel, 2014, https://doi.org/10.1007/978-3-0348-0622-0 . 10.1007/978-3-0348-0622-0Search in Google Scholar

[14] Y. Na , H. Bang , and S. Mok , Vision-based relative navigation using dual quaternion for spacecraft proximity operations, Int. J. Aeronaut. Space Sci. 20 (2019), 1010–1023, https://doi.org/10.1007/s42405-019-00171-8 . 10.1007/s42405-019-00171-8Search in Google Scholar

[15] J. Vince , Rotation Transforms for Computer Graphics, Springer, London, 2011, https://doi.org/10.1007/978-0-85729-154-7 . 10.1007/978-0-85729-154-7Search in Google Scholar

[16] J. P. Ward , Quaternions and Cayley Numbers: Algebra and Applications, Mathematics and Its Applications, vol. 403 , Kluwer Academic Publishers, Dordrecht, the Netherlands, 1997, https://doi.org/10.1007/978-94-011-5768-1 . 10.1007/978-94-011-5768-1Search in Google Scholar

[17] Y. Hong and F. Qi , Inequalities for generalized eigenvalues of quaternion matrices, Period. Math. Hungar. 83 (2021), no. 1, 12–19, https://doi.org/10.1007/s10998-020-00358-7 . 10.1007/s10998-020-00358-7Search in Google Scholar

[18] W. R. Hamilton , Lectures on Quaternions, Hodges and Smith, Dublin, 1853. Search in Google Scholar

[19] B. J. Xie , An expansion theorem for determinants of selfadjoint quaternion matrices and its applications, Acta Math. Sinica 23 (1980), no. 5, 668–683. (Chinese) Search in Google Scholar

[20] B. J. Xie , Applications of characteristic roots and standard forms of matrices over a skew field, Acta Math. Sinica 23 (1980), no. 4, 522–533. (Chinese) Search in Google Scholar

[21] B. J. Xie , Determinants of centralizable matrices over any skew-field, J. Jilin Univ. Natur. Sci. Ed. (Acta Sci. Natur. Univ. Jilin) 3 (1980), 1–33. (Chinese) Search in Google Scholar

[22] B. J. Xie , Self-conjugate matrices and determinants of quaternions, J. Jilin Univ. Natur. Sci. Ed. (Acta Sci. Natur. Univ. Jilin) 2 (1980), 19–35. (Chinese) Search in Google Scholar

[23] W. J. Zhuang , Inequalities for the eigenvalues and singular values of quaternion matrices, Adv. in Math. (Beijing) 17 (1988), no. 4, 403–407. (Chinese) Search in Google Scholar

[24] C. G. Cao , Some theorems on self-conjugate quaternion matrices, J. Math. Res. Exposition 8 (1988), no. 3, 346–348. (Chinese) Search in Google Scholar

[25] P. Catarino and P. Vasco , On matrices with Pell, Pell–Lucas, k-Pell and k-Pell–Lucas quaternions, An. Ştiinţ. Univ. Al. I. Cuza Iaşi. Mat. (N.S.) 64 (2018), no. 2, 373–388. Search in Google Scholar

[26] Z.-H. He , Structure, properties and applications of some simultaneous decompositions for quaternion matrices involving phi-skew-Hermicity, Adv. Appl. Clifford Algebr. 29 (2019), 6, https://doi.org/10.1007/s00006-018-0921-4 . 10.1007/s00006-018-0921-4Search in Google Scholar

[27] Y. Hong , D. Lim , and F. Qi , Some inequalities for generalized eigenvalues of perturbation problems on Hermitian matrices, J. Inequal. Appl. 2018 (2018), 155, https://doi.org/10.1186/s13660-018-1749-0 . 10.1186/s13660-018-1749-0Search in Google Scholar PubMed PubMed Central

[28] T. Jiang , Z. Zhang , and Z. Jiang , Algebraic techniques for eigenvalues and eigenvectors of a split quaternion matrix in split quaternionic mechanics, Comput. Phys. Commun. 229 (2018), 1–7, https://doi.org/10.1016/j.cpc.2018.03.021 . 10.1016/j.cpc.2018.03.021Search in Google Scholar

[29] H. H. Kösal and M. Tosun , Universal similarity factorization equalities for commutative quaternions and their matrices, Linear Multilinear Algebra 67 (2019), no. 5, 926–938, https://doi.org/10.1080/03081087.2018.1439878 . 10.1080/03081087.2018.1439878Search in Google Scholar

[30] Y. Li , M.-S. Wei , F.-X. Zhang , and J.-L. Zhao , On the power method for quaternion right eigenvalue problem, J. Comput. Appl. Math. 345 (2019), 59–69, https://doi.org/10.1016/j.cam.2018.06.015 . 10.1016/j.cam.2018.06.015Search in Google Scholar

[31] B.-Y. Xi and F. Zhang , Inequalities for selected eigenvalues of the product of matrices, Proc. Amer. Math. Soc. 147 (2019), no. 9, 3705–3713, https://doi.org/10.1090/proc/14529 . 10.1090/proc/14529Search in Google Scholar

[32] F. Zhang , Quaternions and matrices of quaternions, Linear Algebra Appl. 251 (1997), no. 2, 21–57, https://doi.org/10.1016/0024-3795(95)00543-9 . 10.1016/0024-3795(95)00543-9Search in Google Scholar

[33] J. L. Brenner , Matrices of quaternions, Pacific J. Math. 1 (1951), no. 3, 329–335, http://projecteuclid.org/euclid.pjm/1103052104 . 10.2140/pjm.1951.1.329Search in Google Scholar

[34] H. C. Lee , Eigenvalues and canonical forms of matrices with quaternion coefficients, Proc. Roy. Irish Acad. Sect. A 52 (1949), 253–260. Search in Google Scholar

[35] R. M. W. Wood , Quaternionic eigenvalues, Bull. London Math. Soc. 17 (1985), no. 2, 137–138, https://doi.org/10.1112/blms/17.2.137 . 10.1112/blms/17.2.137Search in Google Scholar

[36] J. Dieudonné , Les déterminants sur un corps non commutatif, Bull. Soc. Math. France 71 (1943), 27–45. Available at http://www.numdam.org/item?id=BSMF_1943__71__27_0. (French) 10.24033/bsmf.1345Search in Google Scholar

[37] M. L. Mehta , Determinants of quaternion matrices, J. Math. Phy. Sci. 8 (1974), 559–570. Search in Google Scholar

[38] L. X. Chen , Definition of determinant and Cramer solutions over the quaternion field, Acta Math. Sinica (N.S.) 7 (1991), no. 2, 171–180, https://doi.org/10.1007/BF02633946 . 10.1007/BF02633946Search in Google Scholar

[39] B. Y. Xi , Singular value inequalities for quaternion matrix products, J. Math. Res. Exposition 12 (1992), no. 1, 91–94. (Chinese) Search in Google Scholar

Received: 2021-02-09
Revised: 2021-05-17
Accepted: 2021-06-21
Published Online: 2021-07-09

© 2021 Yan Hong and Feng Qi, published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

Downloaded on 25.4.2024 from https://www.degruyter.com/document/doi/10.1515/math-2021-0061/html
Scroll to top button