# Yulia Khalniyazova - Taiga Book - Applications (Highlights) ![rw-book-cover|256](https://readwise-assets.s3.amazonaws.com/static/images/article3.5c705a01b476.png) ## Highlights - Every time the application state is about to change, the application VP is called to validate the state transition. ([View Highlight](https://read.readwise.io/read/01hcv2816244d1pe07h10ry9w6)) ^611211914 Similar to CKB type script - Each application has a unique application identifier that we call an address. The application address is derived from its application VP. ([View Highlight](https://read.readwise.io/read/01hcv26xebdh5jj4bvyjse50z7)) ^611211752 - The application a note belongs to is indicated by the note's type which is derived using the application address, binding the note with the application. ([View Highlight](https://read.readwise.io/read/01hcv27c228xc8a32mk26ffp5j)) ^611211819