Comment on "PT Symmetry as a Generalization of Hermiticity" [arXiv:1002.2676]

We notice that the general PT-symmetric Hamiltonian matrix(N=2) having 6-real parameters fails to reproduce one parameter PT-symmetric matrix.Comment: Title unchanged ,one ref [5] added . Abstract changed . All the previous matrices have been changed consideing the ref[5

Necessary and sufficient conditions for the oscillation of higher-order differential equations involving distributed delays

In this article, we establish necessary and sufficient conditions for the oscillation of both bounded and unbounded solutions of the differential equation \begin{equation} \bigg[x(t)+\int_{0}^{\lambda}p(t,v)x(\tau(t,v))\,\mathrm{d}v\bigg]^{(n)}+\int_{0}^{\lambda}q(t,v)x(\sigma(t,v))\,\mathrm{d}v=\varphi(t)\quad\text{for } t \geq t_{0},\notag \end{equation} where $n\in\mathbb{N}$, $t_{0},\lambda\in\mathbb{R}^{+}$, $p\in C([t_{0},\infty)\times[0,\lambda] \mathbb{R})$, $q\in C([t_{0},\infty)\times[0,\lambda],\mathbb{R}^{+})$, $\tau\in C([t_{0},\infty)\times[0 \lambda],\mathbb{R})$ with $\lim_{t\to\infty}\inf_{v\in[0,\lambda]}\tau(t,v)=\infty$ and $\sup_{v\in[0,\lambda]}\tau(t,v)\leq t$ for all $t\geq t_{0}$, $\sigma\in C([t_{0},\infty)\times[0,\lambda],\mathbb{R})$ with $\lim_{t\to\infty}\inf_{v\in[0,\lambda]}\sigma(t,v)=\infty$, and $\varphi\in C([t_{0},\infty),\mathbb{R})$. We also give illustrating examples to show the applicability of these results

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This brief outlines policy recommendations for supporting student-centered learning at the local, state, and federal level

Платежная система Pay Pal

The article is devoted to the payment system Pay Pal. The problem of this article is to describe the history of the payment system and the status of the Bank. The article talks about creating Pay Pal and the services of the system. many people use this system and remain davolno