PPA Build Error/Tilde In Version

[Will Daniels <mail@xxxxxxxxxxxxxxxxx>]

Hi, I just got the following error from the PPA build system:

After installing, the following source dependencies are still unsatisfied:
libmono-addins-gui0.2-cil(inst 0.3~svn.r90520-1 ! >= wanted 0.3) 
libmono-addins0.2-cil(inst 0.3~svn.r90520-1 ! >= wanted 0.3)
Source-dependencies not satisfied; skipping monodevelop

I would have thought 0.3~svn.r90520-1 >= 0.3 or am I confused about the 
significance of the tilde character in the version? I can't find much 
about this with Google, perhaps someone can explain to me whether it's a 
bug or how the version naming works here?  Maybe the problem has to do 
with the 0.2 in the package name?

Sorry if it's a stupid question!