negative numbers explanation

neps/nep-0488.md

@@ -394,7 +394,7 @@ The $y$ coordinate is determined by the formula: $y = \pm \sqrt{x^3 + 4}$.
 - The second-highest bit marks the point at infinity (if set to 1).
   - For the point at infinity, all bits except the first two should be set to 0; other encodings should be considered as incorrect.
 - To represent the sign of $y$, the third-highest bit in the x encoding is utilized.
-  - If the bit is 0, $y$ is positive; if 1, $y$ is negative. We'll consider the number positive by taking the smallest value between $y$ and $-y$.
+  - If the bit is 0, $y$ is positive; if 1, $y$ is negative. We'll consider the number positive by taking the smallest value between $y$ and $-y$, after reducing them to $[0, p)$.
 
 The encoding for $x \in F_p$ as `[u8; 48]` bytes follows the rules described in the section "Extension fields elements $F_{p}$".
 
@@ -463,7 +463,6 @@ x[0] = x[0] | 0x40;
 ```
 
 #### ERROR_CODE
-
 Validating the input for the host functions within the contract can consume significant gas.
 For instance, verifying if a point belongs to the subgroup is gas-consuming. 
 If an error is returned by the near host function, the entire execution is reverted.