Originally the mathematical theory behind this technology was developed in Sobolev Institute of Mathematics by three famous mathematicians Yuri L. Yershov, Sergey S. Goncharov and Dmitry I. Sviridenko.
So the idea behind semantic modelling is how to make it simpler for non-programmers to communicate with computers. Instead of creating yet another algorithmic language for programming, semantic modelling is focusing on using logical language allowing non-programmers to effectively explain computers what to do (opposed to algorithms describing how). Such semantic models are called executable specifications.
d0sl stands for Delta_0 (delta zero)Semantiс Language.
d0slis a declarative executable specifications language, which is a constructive subset of the first order predicate logic language.d0slsyntax here
Mathematical definition of Delta_0-formulas here. If you are interested in math theory behind please check this list of articles