Algebraic logic

Question

Both Wolfram Alpha and Bing are now providing the ability to solve complex, algebraic logic problems (ie "solve for x, given this equation"), and not just evaluate simple arithmetic expressions (eg "what's 5+5?"). How is this done?

I can read most types of code that might get thrown at me, so it doesn't really make a difference what you use to explain and represent the algorithm. I find that bash makes a really good pseudo-code, not to mention its actually functional, so that'd be ideal. Also, I'm fairly familiar with its in's and out's. Sorry to go ranting on a tangent, but it really irritates me to see people spend effort on crunching out "pseudocode" when they could be getting something 100% functional for just slightly more effort. Anyways, thanks so much for advance.

Search for "symbolic algebra". The most extant example is probably mathematica. These is a simple OpenSource example called mathomatic. — dmckee --- ex-moderator kitten, Jun 14 '09 at 19:49
There is a "How is this done?" in there...before he goes off on the bash in lieu of pseudocode tangent. Come to think of it, I am pretty sure this has been asked before. — dmckee --- ex-moderator kitten, Jun 14 '09 at 19:58
This is a pretty close match: http://stackoverflow.com/questions/348847/introduction-to-computer-algebra-systems — dmckee --- ex-moderator kitten, Jun 14 '09 at 20:01
For some reason, the OP is hell-bent on destroying their own question. — gnovice, Jun 14 '09 at 20:42
Why are people giving upvotes for trollish behavior? The OP shouldn't be rewarded for such things. — gnovice, Jun 14 '09 at 20:47

Igor Krivokon · Answer 1 · 2009-06-14T20:18:09.837

There are 2 main methods to solve:

Numeric methods. Numerical methods mean, basically, that the solver tries to change the value of x until the equation is satisfied. More info on numerical methods.
Symbolic math. The solver manipulates the equation as a string of symbols, by a number of formal rules. It's not that different from algebra we learn in school, the solver just knows a lot of different rules. More info on computer algebra.

score 0 · Answer 2 · answered Feb 22 '11 at 03:41

Wolfram|Alpha (W|A) is based on the Mathematica kernel, combined with a natural language parser (which is also built primarily with Mathematica). They have a whole heap of curated data and associated formula that can be used once the question has been interpreted.

There's a blog post describing some of this which came out at the same time as W|A.

Finally, Bing simply uses the (non-free) API to answer questions via W|A.

Algebraic logic

2 Answers2