Determinants and Their Applications in Mathematical Physics

(Chris Devlin) #1

130 4. Particular Determinants


Referring to the section on differences in Appendix A.8,


φm=∆

m
θ 0

so that


B=A.

The HankelianBarises in studies by M. Yamazaki and Hori of the Ernst


equation of general relativity andAarises in a related paper by Vein.


Define determinantsU(x),V(x), andW, each of order (n+ 1), by bor-

deringAin different ways. Sinceaijis a function ofxandy, it follows that


U(x) andV(x) are also functions ofy. The argumentxinU(x) andV(x)


refers to the variable which appears explicitly in the last row or column.


U(x)=

∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣


x

x
3
/ 3

[aij]n x

5
/ 5

···

x

2 n− 1
/(2n−1)

111 ··· 1 •

∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣


n+1

=−

n

r=1

n

s=1

Arsx

2 r− 1

2 r− 1

, (4.10.24)

V(x)=

∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣

1

1 / 3

[aij]n 1 / 5

···

1 /(2n−1)

xx
3
x
5
··· x
2 n− 1





∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣

n+1

=−

n

r=1

n

s=1

Arsx

2 s− 1

2 r− 1

, (4.10.25)

W=U(1) =V(1). (4.10.26)

Theorem 4.39.


p

2
U

2
(x)+q

2
U

2
(y)=W

2
−AW.

Proof.


U

2
(x)=


i,s

Aisx

2 i− 1

2 i− 1

n

j,r

Ajrx

2 j− 1

2 j− 1

=


i,j,r,s

AisAjrx

2(i+j−1)

(2i−1)(2j−1)

.

Hence,


p

2
U

2
(x)+q

2
U

2
(y)−W

2
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