Text Formatting ⇒ Equation Numbering

[chrisr34000]

Hello!

I'm having the following code:

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$&=& P(u+\displaystyle \sum_{k=1}^{n}(cY_{k}-X_{k})<0$ für ein $n \geq 1)$

}
$&=& P(\displaystyle \sum_{k=1}^{n}(X_{k}-cY_{k})>u$ für ein $n\geq 1)$
}

$&=& P(\displaystyle \sup_{n\geq 1}\sum_{k=1}^{n}(X_{k}-cY_{k})>u)$  &&  \text{ (1.1)}

&\Leftrightarrow\delta(u) =\ P(\sup_{n\geq 1}\sum_{k=1}^{n}(X_{k}-cY_{k})\leq u)

&=&\ P(\sup_{n\geq 1}R_{n}\leq u)\ \square

As you can see, I have a block of equations here and I want to number the equation, where I have \text{(1.1)} automatically with (1.1). The whole block is between "align" tags. However, the align command does not produce numbering for every line, like I was expecting it. I thought that these command, generates numbering for every line and then I just need to cross the other lines off with the \nonumber command. But align, doesn't produce here any kind of numbering.

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\begin{eqnarray}

produces the numbering at the last line only.

How would you fix this?

Thanks!

[Stefan Kottwitz]

Hi,

have a close look at the align environment syntax. This could be a start for you:

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\begin{align}
  &= P(u+\displaystyle \sum_{k=1}^{n}(cY_{k}-X_{k})<0 \text{ für ein } n \geq 1)\nonumber\\
  &= P(\displaystyle \sum_{k=1}^{n}(X_{k}-cY_{k})>u \text{ für ein } n\geq 1)\nonumber\\
  &= P(\displaystyle \sup_{n\geq 1}\sum_{k=1}^{n}(X_{k}-cY_{k})>u)\\
  &\Leftrightarrow\delta(u) =\ P(\sup_{n\geq 1}\sum_{k=1}^{n}(X_{k}-cY_{k})\leq u)\nonumber\\
  &=\ P(\sup_{n\geq 1}R_{n}\leq u)\ \square\nonumber
\end{align}

Stefan

[chrisr34000]

Excellent, that worked! Thanks again!

Is it possible to use the

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align*

command with some command where I can specify which line to be numbered? A

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numberthis

command? It would be easier than using a the

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nonumber

command over and over again...

[Stefan Kottwitz]

If you would like to use just one number for an aligned multiline environment, you could use a split environment inside an equation environment, for getting a vertically centered number, such as:

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\begin{equation}
\begin{split}
  &= P(u+\displaystyle \sum_{k=1}^{n}(cY_{k}-X_{k})<0 \text{ für ein } n \geq 1)\\
  &= P(\displaystyle \sum_{k=1}^{n}(X_{k}-cY_{k})>u \text{ für ein } n\geq 1)\\
  &= P(\displaystyle \sup_{n\geq 1}\sum_{k=1}^{n}(X_{k}-cY_{k})>u)\\
  &\Leftrightarrow\delta(u) =\ P(\sup_{n\geq 1}\sum_{k=1}^{n}(X_{k}-cY_{k})\leq u)\\
  &=\ P(\sup_{n\geq 1}R_{n}\leq u)\ \square
\end{split}
\end{equation}

Then there's no need for \nonumber, further it's also centered if there's an even number of lines.

Stefan