fri, ipa, hypernova entries, update other-notes

public/ringsig.html

@@ -193,7 +193,7 @@ which we can rearrange to
 <p><br></p>
 
 <p>It reminds in some way to the approach to close a box like the one in the picture:
-<img src="img//posts/ring-sig/box-closed.png" alt="" /></p>
+<img src="img/posts/ring-sig/box-closed.png" alt="" /></p>
 
 <p><br><br><br></p>
 
@@ -286,6 +286,7 @@ assert c1 == c[0]
             {left: '$', right: '$', display: false},
             {left: "\\[", right: "\\]", display: true},
             {left: "\\(", right: "\\)", display: false},
+            {left: "\\begin{equation}", right: "\\end{equation}", display: true}
           ],
           // • rendering keys, e.g.:
           throwOnError : true