How to write a math abstract for a conference in an experimentalist dominated field without "specific numerical results"
Writing as a mathematical modeler in Epidemiology, and a regular submitter to conferences with these types of requirements, which are dominated by empirical research findings, this is something that's hard, if you approach it from the direction you have - with the numerical results coming at the "end" of your research.

It would be good to have a numerical result, because as has been mentioned, while you might not view these as the crux of your research, it may very well be the crux of why someone is interested in your research. Even as someone who does appreciate the theory side of things, I'm often rather more interested in the numerical results.

That being said, these conferences are mostly looking to avoid "Will be discussed" results, where there's no means to evaluate if you've done anything, or if it will be interesting. The latter is especially hard for deciding whether a presentation becomes an oral or poster presentation, because giving one of the precious oral slots to someone whose going to largely be discussing a slew of null results is (often) irksome.

You do however have results, and that should be enough to make it past the bar. If X and Y are both possible within the parameter space, and that means something for the field, then that is a specific result, and you should expand on why that's interesting.