Vector notation for "not including" index

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I was wondering how to write vector notation with an index which is not included in the vector. In sets we can write,

$$ A=\{0,1,2,3,4\},$$

then if we don't want to include the element $\{0\}$ we can write,

$$A \setminus \{0\}=\{1,2,3,4\}.$$

Is there a way to write that for a vector?

i.e. for vector $a=(a_0,a_1,a_2,a_3,a_4)$ can we write $a\setminus a_0=(a_1,a_2,a_3,a_4)$?

Thank you very much.

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There is a way to do this, but it's not convenient or useful. However, I thought I'd share it.

Consider the vector $a=(a_0,a_1,a_2)$. What is this vector? It's a set of ordered pairs. Specificially, this vector in $\mathbb{R}^3$ is defined as $\left\{(0,a_0),(1,a_1),(2,a_2)\right\}$. Let's suppose we wanted the vector $(a_0,a_1)\in\mathbb{R}^2$. We could write this vector as $a \setminus (2,a_2)$.

No one really thinks of vectors as sets as I've described, so it'd be confusing for almost everybody, but it can be done. :)

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Maybe you're looking for projections rather than a difference operation?