Erect means build or upright. If you erect a house, you build it. If you stand erect, you hold your body as tall as possible.
A mathematical model is a description of a system using mathematical concepts and language.The process of building a mathematical model is termed mathematical modeling.Mathematical models are used in the natural sciences (such as physics, biology, earth science, meteorology) and engineering disciplines (e.g. computer science, artificial intelligence). mathematical model is a description of a system using mathematical concepts and language.
Threat modeling is a fundamental activity of the SDL and the main software engineering artifact that results from following the SDL. A threat model is a diagram that encapsulates the various interactions of your envisioned application or service to include both internal and external factors.