Difference between revisions of "Integers"

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|+$\mathbb{T}=\mathbb{Z}$
 
|+$\mathbb{T}=\mathbb{Z}$
 
|-
 
|-
|Generic element $t\in \mathbb{T}$:
+
|Generic element $t\in \mathbb{T}$
 
|For some $n \in \mathbb{Z}, t =n$
 
|For some $n \in \mathbb{Z}, t =n$
 
|-
 
|-
|Jump operator:
+
|Jump operator
 
|$\sigma(t)=t+1$
 
|$\sigma(t)=t+1$
 
|-
 
|-
|Graininess operator:
+
|Graininess operator
 
|$\mu(t)=1$
 
|$\mu(t)=1$
 
|-
 
|-
|[[Delta_derivative | $\Delta$-derivative:]]
+
|[[Delta_derivative | $\Delta$-derivative]]
 
|$f^{\Delta}(t)=f(t+1)-f(t)$
 
|$f^{\Delta}(t)=f(t+1)-f(t)$
 
|-
 
|-
|[[Delta_integral | $\Delta$-integral:]]
+
|[[Nabla derivative | $\nabla$-derivative]]
| $\displaystyle\int_s^t f(\tau) \Delta \tau = \displaystyle\sum_{k=s}^{t-1} f(k)$
+
|$f^{\nabla}(t)=f(t)-f(t-1)$
 +
|-
 +
|[[Delta_integral | $\Delta$-integral]]
 +
| $$\int_s^t f(\tau) \Delta \tau = \left\{ \begin{array}{ll}
 +
\sum_{k=s}^{t-1} f(k) &; t > s \\
 +
0 &; t=s \\
 +
-\sum_{k=t}^{s-1} f(k) &; t < s
 +
\end{array} \right.$$
 +
|-
 +
|[[Nabla integral | $\nabla$-integral]]
 +
| $$\int_s^t f(\tau) \nabla \tau = \left\{ \begin{array}{ll}
 +
\displaystyle\sum_{k=s+1}^t f(k) &; t>s \\
 +
0 &; t=s \\
 +
-\sum_{k=t+1}^s f(k) &; t<s
 +
\end{array} \right.$$
 
|-
 
|-
 
|[[Exponential_functions | Exponential function]]:
 
|[[Exponential_functions | Exponential function]]:

Revision as of 20:36, 20 October 2014

The set $\mathbb{Z}=\{\ldots,-2,-1,0,1,2,\ldots\}$ of integers is a time scale.

$\mathbb{T}=\mathbb{Z}$
Generic element $t\in \mathbb{T}$ For some $n \in \mathbb{Z}, t =n$
Jump operator $\sigma(t)=t+1$
Graininess operator $\mu(t)=1$
$\Delta$-derivative $f^{\Delta}(t)=f(t+1)-f(t)$
$\nabla$-derivative $f^{\nabla}(t)=f(t)-f(t-1)$
$\Delta$-integral $$\int_s^t f(\tau) \Delta \tau = \left\{ \begin{array}{ll} \sum_{k=s}^{t-1} f(k) &; t > s \\ 0 &; t=s \\ -\sum_{k=t}^{s-1} f(k) &; t < s \end{array} \right.$$
$\nabla$-integral $$\int_s^t f(\tau) \nabla \tau = \left\{ \begin{array}{ll} \displaystyle\sum_{k=s+1}^t f(k) &; t>s \\ 0 &; t=s \\ -\sum_{k=t+1}^s f(k) &; t<s \end{array} \right.$$
Exponential function: $\begin{array}{ll} e_p(t,s) &= \exp \left( \displaystyle\int_{s}^{t} \dfrac{1}{\mu(\tau)} \log(1 + p(\tau)) \Delta \tau \right) \\ &= \exp \left( \displaystyle\sum_{k=s}^{t-1} \log(1+p(k)) \right) \\ &= \displaystyle\prod_{k=s}^{t-1} \left( 1+p(k) \right) \\ \end{array}$
$\mathrm{sin}_p(t,0)$ $$\begin{array}{ll} \sin_p(t,t_0) &= \dfrac{e_{ip}(t,t_0)-e_{-ip}(t,t_0)}{2i} \\ &= \dfrac{\displaystyle\prod_{k=t_0}^{t-1}1+ip(k) - \displaystyle\prod_{k=t_0}^{t-1}1-ip(k)}{2i} \end{array}$$
$\mathrm{sin}_1(t,0)$ $$\begin{array}{ll} \sin_1(t,0) &= \dfrac{(1+i)^{t}-(1-i)^{t}}{2i} \\ &= \dfrac{\displaystyle\sum_{k=0}^{t} {t \choose k} i^k - \displaystyle\sum_{k=0}^{t} (-1)^k {t \choose k} i^k}{2i} \end{array}$$

Sin 1T=Z.png

$\mathrm{cos}_p(t,t_0)$ $$\begin{array}{ll} \cos_p(t,t_0) &= \dfrac{e_{ip}(t,t_0)+e_{-ip}(t,t_0)}{2} \\ &= \dfrac{\displaystyle\prod_{k=t_0}^{t-1}1+ip(k) + \displaystyle\prod_{k=t_0}^{t-1}1-ip(k)}{2} \end{array}$$
$\mathrm{cos}_1(t,0)$ \begin{array}{ll} \cos_1(t,0) &= \dfrac{(1+i)^{t}+(1-i)^{t}}{2} \\ &= \dfrac{\displaystyle\sum_{k=0}^{t} {t \choose k} i^k + \displaystyle\sum_{k=0}^{t} (-1)^k {t \choose k} i^k}{2} \end{array}

Cos 1T=Z.png

Hilger circle Hilgercircle,T=Z.png
Gamma function: $\Gamma_{\mathbb{Z}}(t;s)=\displaystyle\sum_{k=0}^{\infty} \left( \displaystyle\prod_{j=s}^{k-1} \dfrac{j+x}{j+1} \right) \dfrac{1}{2^{k+1}}$