Representation of this function using a single formula without conditions Is it possible to represent the following function with a single formula, without using conditions? If not, how to prove it?
$F(x) = \begin{cases}u(x), & x \le 0, \ v(x) & x > 0 \end{cases}$
So that it will become something like that: $F(x) = G(x)$ With no conditions?
I need it for further operations like derivative etc.

Note: This answers the original question, asking whether a formula like $F(x)=G(u(x),v(x))$ might represent the function $F$ defined as $F(x) = u(x)$ if $x \leqslant 0$ and $F(x)=v(x)$ if $x > 0$. 

The OP finally reacted to remarks made by several readers that another answer did not address this, by modifying the question, which made the other answer fit (post hoc) the question.

Just to make sure @Rasmus's message got through: for any set $E$ with at least two elements, there can exist no function $G:\mathbb R^2\to E$ such that for every functions $u:\mathbb R\to E$ and $v:\mathbb R\to E$ and every $x$ in $\mathbb R$, one has $G(u(x),v(x))=u(x)$ if $x\leqslant0$ and $G(u(x),v(x))=v(x)$ if $x>0$.
