Guide for New Users

Approach0 is a third-party search engine dedicated to provide better search experience for mathematical Q&A websites. This page aims to provide new users a quick tour about how to use Approach0 search engine.

What is Approach0?

Approach0 is a math-aware similarity search engine, which means you type a query containing one or more “keywords”, each keyword can be either normal text or a math expression. Then the search engine gets you search results from already indexed posts/threads which contain the content you may find relevant to your query.

What the search engine actually looks for?

This search engine only indexes Mathematics StackExchange site right now.

Currently it has finished indexing most posts on Math SE site. Although newly updated posts may not be renewed in our database immediately due to limited hardware resource we currently have, we are trying our best to renew the index on a regular basis, usually every week or so (depending on how lazy the maintainer is at that time).

How a search query is entered?

1. Non-math keyword

If you only want to search non-math terms (i.e. normal text), just type the keyword(s) like what you normally do on a typical search engine:

(After you have done a keyword, hit Enter to finish editing, then hit Enter again or click search button to actually perform search)

2. Math keyword

To input math keyword is also very intuitive, user does not have to know TeX to input a math expression on search box. Below is an example of inputting math expression \(\log(x)\):

You can either type \log(x) or log(x) directly on search box to input \(\log(x)\). Although this works, the recommended way is first type a dollar sign $ (to indicate the next keyword you are entering is a math keyword) followed by your math expression.

This is important when you are entering a math expression that is hard to tell whether it is truly a math or a regular term. (e.g. AI can be interpreted as a matrix multiplication in math or “Artificial Intelligence” in English)

3. Mixed keywords

You can mix non-math and math keywords together (in any order) within one query:

One restriction: You are limited to enter less than 5 math keywords and less than 21 non-math keywords in one query.

Other tips

  • There are some math symbols that you may find not intuitive or not familiar on how to type directly into query input box (such as \( \infty \), \( \Theta \) and \( \perp \)). In these cases, click “handy pad” under search box for a number of buttons to help you enter math symbols.
  • The URL displayed on your browser uniquely determines a query and page you are searching for. So you can show this URL to others to refer a query.
  • We support copy-paste in query input box. For math keyword, paste a/b and $a/b$ into query box both result in the same math expression \(\dfrac a b \).
  • You can edit or delete a math keyword by clicking the or × icon on the right of the keyword. You can also delete (but no edit option) a non-math keyword by clicking the × icon on the right of the keyword.
  • If you do not get any search result (“No hit found”), try to reduce the complexity of your math expression a little bit. Also, check if your raw query is somewhat malformed, by clicking the raw query link under search box. Some typical malformed TeX snippets:
    • a^(1+2+3) (should be a^{1+2+3})
    • sin(x) (should be \sin(x))
  • How to manually enter (without the assistance of “handy pad”) integrals with both lower and upper bounds?
    • This is a little tricky, the wrong way:
    • The right way: Use arrow key to move cursor to the rightmost and hit a ^ so it goes to upper bound edit. Then hit tab key to move cursor to edit function \( f(x) \):

Advanced Usage

  • If you know math-related TeX commands, it is often faster to edit the equivalent raw query (separate keywords by commas). For example, the above mixed keywords “concave” and “\(f’’ < 0\)” is equivalent to inputting a concave, $f''\lt 0$ in raw query box.
  • You can use question mark ? on our query input box to represent a wildcard which represents any math expression except a single symbol. For example, if you want to search expression \[dX_t = \ln (1+X_t^2)+ X_t dB_t \] you can type less by just searching: \[ ? = \ln (1+X_t^2)+ ? \] In raw query, you can use \qvar{} to name wildcards which represent different expressions. For instance: $\qvar{x} = \ln (1 + X_t^2) + \qvar{y}$.
  • Our WEB API enables developers to build their own applications based on our search engine. Search results are returned in JSON format.

Help Approach0 improve

Approach0 starts from a side-project, although having the feeling that this project will be potentially useful, the author cannot focus on it with full-time effort. Everyone is invited to contribute to this project. Below are some ways you can help to improve Approach0.

1. Make contribution to this project

Approach0 is an open-source project hosted on Github. And it is open to any brilliant idea.

Notice each time you visit approach0 there will be a “random” math question which is called “quiz conversation”, You can contribute your own quiz conversation on this page.

2. Improve this page

Click the upper-right Edit on GitHub link to request modify this page if you spot some error or if you want to share with others your tricks on using Approach0.

3. Send feedbacks

Got any suggestion? Write your thoughts on our GitHub issue page. Or, if you are not familiar with GitHub, you can send feedback messages to this project on twitter with hashtag #approach0.

Your participation is a great incentive for Approach0 to keep moving forward!