10 A. CASTRO AND V. PADR

´

ON

✻

✲

d

1

λ

μ1

p−q

ν2

p−q

μ2

p−q

ν3

p−q

μ3

p−q

νn

p−q

μn

p−q

ψ2 ψ3 ψn

ξ1 ξ2 ξ3 ξn

Figure 4. Bifurcation curves defined by the functions ξj (contin-

uous line), and ψj (dotted line) for the case −1 q 1, p ≥

N+2

N−2

.

✻

✲

d

D

1

λ

μ1

p−q

ν2

p−q

μ2

p−q

ν3

p−q

μ3

p−q

νn

p−q

μn

p−q

ψ2 ψ3 ψn

ξ1 ξ2 ξ3 ξn

Figure 5. Bifurcation curves defined by the functions ξj (contin-

uous line), and ψj (dotted line) for the case −1 q p 1.