Core subdomain is one of the three subdomains of the Business Domain. Core subdomain is the most important, because it is the one that differentiate the business from its competitors and gives an advantage over the others. Core subdomain doesn’t have to be innovative; it may be a solution that helps the business to cut the costs dramatically.
Core subdomains are complex
Core subdomains should be difficult to implement (after all, nothing like that exists yet). They also should be difficult to copy by competitors; if they are easy to copy, there’s no real value in the product and competitors will quickly catch up.
Core subdomains are novel
Core subdomain has to be novel. They need to provide something that is unique and doesn’t exists yet on the market. If it already exists, it doesn’t really add any value for people and will not attract customers or investors.
Core subdomains always evolve
Core subdomain do not stagnate. This is something that should always evolve by adding new features or optimising things to have better ROI. It is what helps you to stay ahead of competitors.
Implementation
Core domains should most most likely be implemented in-house. An external company should not be able to work on it, nor should be something that can be bought or adopted. If that is the case, your competitors would be able to do the same. This is where you should not cut the corners