Because I want to use matrices in my program, I added the Math.NET library through NuGet in Visual Studio 2015. However, although I can see the library files in the Project References folder, VS doesn't seem to recognize any of the references to it. Autocomplete won't suggest MathNet when writing the using-command, and it won't recognize any of the classes from that namespace either, of course. Are there any more steps I'm missing?
While I still can't say why autocomplete didn't suggest the namespace (even though after attempting to build it it did end up showing in the suggestions), I can confirm that the source of my problem was that matrices and vectors need to be imported with MathNet.Numerics.LinearAlgebra, not MathNet.Numerics.