# Yulia Khalniyazova - Taiga Book - Validity Predicates (Highlights) ![rw-book-cover|256](https://readwise-assets.s3.amazonaws.com/media/uploaded_book_covers/profile_155788/taiga) ## Metadata **Review**:: [readwise.io](https://readwise.io/bookreview/33229058) **Source**:: #from/readwise #from/reader **Zettel**:: #zettel/fleeting **Status**:: #x **Authors**:: [[Yulia Khalniyazova]] **Full Title**:: Taiga Book - Validity Predicates **Category**:: #articles #readwise/articles **Category Icon**:: 📰 **URL**:: [github.com](https://github.com/anoma/taiga/blob/main/book/src/validity-predicates.md) **Host**:: [[github.com]] **Highlighted**:: [[2023-10-16]] **Created**:: [[2023-10-16]] ## Highlights - A **validity predicate** is a piece of code defined by an application that authorizes transactions the application is involved in. ([View Highlight](https://read.readwise.io/read/01hcv2qczyvq3wjdy7gfy8g3nr)) ^611213926 similar: CKB types cript - Validity predicates in Taiga have a hierarchical structure. For all applications involved in a transaction, their `ApplicationVP` must be checked. These VPs might require validity of some other VPs in order for a transaction to be considered valid. In that case, those other VPs must be checked too. ([View Highlight](https://read.readwise.io/read/01hcv2sdq5pzj2ccwx8rwjvven)) ^611214126 CKB lacks of a type script hierarchical structure.