Determinants and Their Applications in Mathematical Physics

(Chris Devlin) #1
5.1 Determinants Which Represent Particular Polynomials 175

But


a


ij
+ai− 1 ,j=

[(

j− 1

i− 1

)

+

(

j− 1

i− 2

)]

u

(j−i+1)


[(

j− 1

i− 2

)

+

(

j− 1

i− 3

)]

v

(j−i+2)

=

(

j

i− 1

)

u

(j−i+1)

(

j

i− 2

)

v

(j−i+2)

=ai,j+1. (5.1.13)

Hence,


C


j+C


j=Cj+1, (5.1.14)

A


n=

n

j=1



C 1 C 2 ···C


jCj+1···Cn−^1 Cn



n

,

A

(n+1)
n+1,n

=−


∣C

1 C 2 ···CjCj+1···Cn− 1 Cn+1



n

. (5.1.15)

Hence,


A


n+A

(n+1)
n+1,n

=

n

j=1



C 1 C 2 ···(C


j−Cj+1)Cj+1···Cn



n

=−

n

j=1


∣C

1 C 2 ···C


j
···Cn



=0

by Theorem 3.1 on cyclic dislocations and generalizations in Section 3.1,


which proves (a).


ExpandingAn+1by the two elements in its last row,

An+1=(u−nv


)An−vA

(n+1)
n+1,n

=(u−nv


)An+vA


n

=v

[

A


n

+

(

u

v


nv


v

)

An

]

,

yAn+1

v
n+1

=

y

v
n

[

A


n

+

(

y

y


nv

v

)

An

]

=

yA


n

v
n

+

(

y

v
n

)′

An

=D

(

yAn

v
n

)

=D

2

(

yAn− 1

v
n− 1

)

=D

r

(

yAn−r+1

v
n−r+1

)

, 0 ≤r≤n
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