Is there a math symbol for $f(x) > g(x)$ except when $x=0$, in which case $f(x)=g(x)$? Title says it all, except that $x \in R^n$.     For want of a better choice, I've specified the amsmath symbol $\gtrdot$ for this relation, but probably this actually means something quite different that google hasn't revealed??    If no such symbol exists, and my choice means something different, does anybody have an alternative suggestion?      Thanks very much!

You could define a Boolean function: $$D^+(f, g) = \delta^{f(0)}_{g(0)} | f(x) > g(x) \forall x \neq 0 |$$ Presumably everyone reading your paper knows what the Kronecker delta and the Iverson bracket are. It's much easier to look for a prior definition of a function than it is to look for a prior use of a symbol, as you yourself have already experienced.
For example, if $f(x) = 3x^2$ and $g(x) = \frac{x^2}{3}$, then $D^+(f, g) = 1$. But with the prime counting function $\pi_1(x)$ and the semiprime counting function $\pi_2(x)$, we'd have $D^+(\pi_1, \pi_2) = 0$ because we also have $\pi_1 = \pi_2$ for $-2 < x < 2$.
Then, later on, to use Bob's example, you could write $D^+(\alpha, \beta) = 1$.
