起始为指数律的p-函数振荡问题

THE OSCILLATION OF p-FUNCTIONS WITH EXPONENTIAL START

  • 摘要: 设 g 是标准 p-函数类. 对 u>0 令\mathscrg(u)=\left\p \in \mathscrg: \exists q \geqslant 0, p(t)=e^-q t, 0 \leqslant t \leqslant u\right\在 9 Kingman 证明了: 如果 p \in \mathscrF(u) 则 p(t) \leqslant e^-1+e^-q u(t \geqslant u) ,而在4中 Griffeath 进一步证明了: p(t) \leqslant e^-(1-\sigma u)(t \geqslant u) 。本文首先给出这一结果一个完全不同的新证明. 然后证明下面的结果:如果p \in \mathscrF(u), s \geqslant u, M=\max _u< i< 1 p(t), m=P(s) 则 p(t) \leqslant \max \left(M, m+e^-1+m\right)(t \geqslant u).本文的第二个结果叙述如下: 记\begingatheredm(M, p)=\inf \p(t): 0 \leqslant t \leqslant 1, p(1)=M\, p \in \mathscrG \\I(M, u)=\inf \left\m(M, p): p \in \mathscrF^\prime(u)\right\, I(M)=\inf \m(M, p): p \in \mathscrP\ \\I^*(M)=\lim _u \downarrow 0 I(M, u), v_0=\inf \M>0: I(M)>0\ \\v^*(M)=\inf \left\M>0: I^*(M)>0\right\ \text 则 v_0=v^* .\endgathered

     

    Abstract: Let \mathscrP be the set of all standard p-functions. For u>0 let \mathscrP(u)=\left\p \in \mathscrP: \exists q \geqslant 0, p(t)=e^-q t, 0 \leqslant t \leqslant u\right\ In 9. Kingman proved: if p \in \mathscrP(u) then p(t) \leqslant e^-1+e^-q u(t \geqslant u), and Griffeath ^4 further proved: p(t) \leqslant e^-\left(1-e^-q u)\right.(t \geqslant u). In this paper we first give Griffeath's result a new proof, and then prove the following rusult: if p \in \mathscrP(u), s \geqslant u, M=\max _u< t< s p(t), m=p(\mathbfs), then p(t) \leqslant \max \left(M, m+e^-1+m\right)(t \geqslant u). The second result of this paper is as follows. Let \begingathered m(M, p)=\inf \p(t): 0 \leqslant t \leqslant 1, p(1)=M\, \quad p \in \mathscrP \\ I(M, u)=\inf \m(M, p): p \in \mathscrP(u)\ \quad I(M)=\inf \m(M, p): p \in \mathscrP\; \\ I^*(M)=\lim _u \downarrow 0 I(M, u) ; v_0=\inf \M>0: I(M)>0\; \\ v^*=\inf \left\M>0: I^*(M)>0\right\ \endgathered then v_0=v^*.

     

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