That's true about floating point numbers. I assume that depending upon the context, it may not be a big issue (e.g. GPU compute)? In any case, the point Stepa

That's true about floating point numbers. I assume that depending upon the context, it may not be a big issue (e.g. GPU compute)? In any case, the point Stepanov was making is that if you want to be able to use a certain algorithm, then you have to make a choice to represent your data in a way that enables that algorithm, and the way you know whether the structure is appropriate for that algorithm is the algebraic properties of the structure.