Topology Framework .NET (TF.NET) represents a topology manipulation API capable of handling managed objects representation of topological entities based on other popular APIs, exposing it's JTS-based common topology manipulation core to them.
JTS Topology Suite is, in fact, Java API providing spatial object model and fundamental geometric functions, providing a complete, consistent, robust implementation of fundamental 2D spatial algorithms. It implements geometry model defined in the OpenGIS Consortium Simple Features Specification for SQL. JTS port for .NET was named NTS, and is fully conformant to Microsoft .NET 2.0 specification. NTS extends JTS with numerous coordinate transformation and other functions, while TF.NET extends NTS further, including additional IO functions and generic classes related to geometry graphs. For details regarding described technologies and their respective authors see acknowledgements below.
Please see https://github.com/SesticM/tf-net/wiki for more info.