 Open Access
 Total Downloads : 1
 Authors : Paramjeet Sangwan
 Paper ID : IJERTCONV1IS02030
 Volume & Issue : NCEAM – 2013 (Volume 1 – Issue 02)
 Published (First Online): 30072018
 ISSN (Online) : 22780181
 Publisher Name : IJERT
 License: This work is licensed under a Creative Commons Attribution 4.0 International License
CAYLEYHAMILTON THEOREM for SQUARE and RECTANGULAR MATRICES and BLOCK MATRICES
CAYLEYHAMILTON THEOREM FOR SQUARE AND RECTANGULAR MATRICES AND BLOCK MATRICES
Paramjeet Sangwan
Assistant Professor, Geeta Engineering College, Naultha Panipat mathematicsat2012@gmail.com
Abstract: The main aim of the paper is to introduce cayley Hamilton Theorem and also to explain its extension for the square and rectangular matrics. In this paper CH Theorem extension for block matrics has also explained.
Keywords: Cayley Hamilton Theorem, topology, Matrices, square, rectangular , block.

INTRODUCTION
Defintion 1.1. If A is an nÃ—n matrix ,then the characteristic polynomial of A is defined to be PA(x)= det(xIA). This is a polynomial in x of degree n with leading term xn . the constant term c0 of a polynomial q(x) is interpreted as c0 I in q(A).
Theorem 1.2 (Cayley Hamilton Theorem). If A is an nÃ—n matrix ,then pA(A)=0, the zero matrix.
Theorem 1.3 If q0 is a quaternion of the form q= a+bi+cj+dk with a,b,c,d, being real , then q2 – 2aq + (a2
2 2 2
If one represents a quaternion q= a+bi+cj+dk as a matrix, A =[ a + bi c + di],
c + di a bi
PA(A) = A2 2aA+(a2 + b2 + c2 + d2)I = 0, and the polynomial given in Theorem 1.3 is characteristic polynomial of A

GENERALIZATION OF CAYLEY HAMILTON
THEOREM
Theorem 2.1 (CayleyHamilton Theorem). For any n Ã— n Matrix A, PA(A)=0.
Proof. Let D(x) be the matrix with polynomial entries D(x)= adj(xInA), So D(x)(xIA)= det(xInA)In. Since each entry in D(x) is the determinant of an (n1) X( (n1) submatrix of (xInA), each entry of D(x) is a polynomial of degree less than or equal to n1. It folowws that there exist matrices D0, D1,Dn1 with entries from C such that
+b +c +d )=0
q1 = q
q
abicjdk
= a2+b2+c2+d2
2a
a+bi+cj+dk
D(x) = Dn1 xn1++ D1 x +Do . Then the matrix equation follows
det(xInA) In = (x InA) adj(xInA) = (xInA)D(x)
Substituting pA(x)= det(xInA), (and using the fact that scalars commute with matrix)
XnIn+ bn1xn1In+.+ b1xIn+b0In
= a2+b2+c2+d2 a2+b2+c2+d2
1
= a2+b2+c2+d2 (2a q)
a2 + b2 + c2 + d2 = 2aq q2
q2 2aq + (a2 + b2 + c2 + d2) = 0
= pA(x) In= det(xInA)In
=(xInA)adj(xInA)
=(xInA)(xn1Dn1++xD1+Do)
=xnDn1 xn1ADn1+ xn1Dn2xn2ADn2++ xD0ADo
=xnDn1+ xn1 (ADn1+ Dn2 ) +..+(AD1+Do) ADo
m ami[Ani Ani1A2] = 0mn (3.5)
i=O 1 1
Since two polynomials are equal if and only if their coefficients are equal , the coefficient matrices are equal ;
Where 0mn is the (mÃ—n) matrix. Theorem 3. Let ,
that is , In=Dn1, bn1In= ( ADn1+Dn2),,b1In=
(AD1+D0), and b0In=AD0. This means that A may be
A
1
A = A2 C
mÃ—n
, m > n
substituted for the variable x in the equation (2.1) to conclude
PA(A) = An+ bn1 An1++ b1A+b0In
and let the characteristic polynomial of A1 have the form . Then
Ami
n n1
n i=O
ani
1
A2Ami1
= 0mn
(3.6)
=A Dn1+A
(ADn1 +Dn2)++A(AD1+D0)AD0 1
=AnDn1AnDn1+An1Dn2 An1Dn2+.AD0AD0
=0 This proves the theorem

CAYLEYHAMILTON THEOREM FOR SQUARE AND RECTANGULAR MATRICES
Let CnÃ—m be the set of complex (nÃ—m) matrices.
Theorem 1. (CayleyHamilton theorem). Let
p(s) = det[Ins A]

CAYLEYHAMILTON THEOREM FOR BLOCK MATRIX
The classical CayleyHamilton theorem can be also extended for block matrices.
Theorem 4. (CayleyHamilton theorem for block matrices).
Let
A11 A1m
n A =
CmnÃ—mn
= L aisi (an = 1)
i=O
(3.1)
Am1 Amm
where Aij CnÃ—nare commutative i.e.,
(4.1)
be the characteristic polynomial of A, where In is the (nÃ—n) identity matrix. Then
Let
AijAkl = AklAij for all i,j,k,l = 1,2,.,m
(4.2)
i=O
p(A) = n
aiAi = 0n (3.2)
P(S) = det[Im A] = Sm
+ D1S
m1
+ +
Where 0n is the (nÃ—n) matrix.
The classical CayleyHamilton theorem can be extended to rectangular matrices as follows [16]
Theorem 2. (CayleyHamilton theorem for rectangular matrices).
Let
A = [A1 A2] CmÃ—n, A1 CmÃ—m, A2
Dm1S + Dm
(4.3)
be the matrix polynomial of A , where S CnÃ—n is the block matrix having eigenvalue of A, denotes the Kronecker product of matrix .
Then
CmÃ—(nm), (n > m) (3.3)
P(A) = m
[ImDmi
]Ai = 0 (DO
= In) (4.4)
i=O
and
The matrix (4.3) is obtained by developing the determinant
pA1
= det[Ims A1] = m
aisi (am = 1) (3.4)
of the matrix [In
S A] , considering its commuting
i=O
be the characteristic polynomial of A1. Then
block as scalar entries.
Theorem 5. (Cayley Hamilton Theorem for rectangular block matrices)
Let A = [A1 A2] CmnÃ—(mn+p) and let matrix
charactristics polynomial of A have the form (4.3.2), then

D.R. Wilkins, Linear Operators and the Cayley Hamilton Theorem , available from http://www.maths.tod.i.e/pub/histMath/people/Hamilton
, 2005

Raghib Abu Saris and Wajdi Ahmad, Avoiding Eigen values in Computing Matrix Powers. The
m
i=O
[Im Dmi][Ai+1 AiA2] = 0 (DO = In) (4.5)Mathematical Association of America 112(2005),
Theorem 6. Let
450454.

Kaczorek T., 1988. Vectors and Matrices in Automation and Electrotechnics, WNT Warszawa (in Polish).
A = A C(mn+p)Ã—mn , A C A2
CpÃ—mn
mnÃ—mn
, A2

Kaczorek T., 1995. An existence of the CayleyHamilton
theorem for nonsquare block matrices and computation of the left and right in verses of matrices, Bull. Pol. Acad.Techn. Sci., vol. 43, No 1, pp. 4956.
and let the matrix characteristic polynomial of A have the form , then

Kaczorek T., 1998. An extension of the Cayley Hamilton theorem for a standard pair of block matrices, Appl Math. And Com. Sci., vol. 8, No 3, pp. 511516.
m
A
L A [Im Dmi]Ai = 0 (DO = In)
2
i=O


CHARACTERSTICS
The Cayley Hamilton theorem is one of the most powerful and classical matrix theory theorem. Many application derive their results from this theorem. To understand the scope of this theorem , alternate proofs were used. Each proof helped to understand how intertwined areas of mathematics are with respect to matrices and the characteristics polynomial.

APPLICATION OF CAYLEY HAMILTON
THEOREM
A very common application of the Cayley Hamilton Theorem is to use it to find An usually for the large powers of n. However many of the techniques involved require the use of the eigen values of A.
REFERENCES

William A. Adkins and Mark G. Davidson, The Cayley Hamilton and Frobenious theorems via the Laplace Transformation, Linear Algebra and its Applications 371(2003), 147152.

Arthur Cayley, A memoir on the theory of Matrices, available from http:// www.jstor.org, 1857.

Wikipedia , Arthur Cayley, Available from http:// en.wikipedia .org, 2004

Wikipedia, William Rowan Hamilton, Available from http:// en. wikipedia .org, 2005