I assume something has broken, but this article makes no sense to me. It's full of sentences like:
"If is very similar to , and is different from , then we do not need to compute to know that and are also very different."
"If is very similar to , and is different from , then we do not need to compute to know that and are also very different."
(The page is running MathJax to convert MathML to HTML + CSS)