I have just modified the UI a little, here is the new looking: 45.79.114.212/search (same link)
Now, I am going to re-index and re-distribute the index load of search engine instances, hopefully I can further speed it up. Meanwhile, if you have any suggestion, please let me know. I would like to replace the current official website with v3 as soon as possible, just to save my wallet :P
BTW. Here is some new features of v3 that I would like you to know if you want to test it: 1) handle mixed text and formula enclosed by dollars without the need to have comma separated. (the case brought up by @user153330). 2) Better search recall. No more restriction on matching among constants vs. variable token, eliminate the impact of sup/subscripts in most cases, e.g., definite and indefinite integrals, variable w/ subscript or w/o subscript. 3) Being able to match rearranged terms.
