I am interested in functions of the form $\psi: F^n \to \mathbb{R}^+$, where $F$ is a finite field, that have norm-like properties, e.g., $\psi(x+y) \le \psi(x) + \psi(y)$. Does anybody know if there is any literature on this area?


Question: Android- R.java file not found
Answer: 
click  Project --> Build Automatically
check build automatically
clean the project