The working factorial

Continuing from Experiments with a little lisper tutorial, recall that at that moment I succeeded to compute with chemlambda a relative of the factorial, but not the factorial itself.

Now, I learned how to do it and it works all the time (compared with 20% success last time).

Last time I took a lambda term for the factorial from the lambda calculus tutorial by Mayer Goldberg from the, par. 57, page 14. Then I modified it and got a molecule which computes the factorial in about 20% of the cases. Now, in this working factorial example, I made two supplementary modifications. The first consists in starting from a lambda term which uses the mutiplication in the form L mnf.m(nf) instead of the one used in the tutorial. Secondly, the result of the computation (i.e. the “value” of the factorial) is applied to a SUCC (successor) which is then applied to c0, which result in the generation of the correct result.

Link to the demo with factorial(4)=24.

Here is the video, recorded as seen in safari, with 2X speed (firefox behaves crappy with the d3.js demos I make, have no precise idea why; that is why I recorded my experience with the demo, then re-recorded the video with 2X speed, all this done with QuickTime)

It works very well also with factorial(5)=120, but because the visualization of that computation takes some time (which may challenge people with short attention span), here is a video with the last part of the computation at 8X speed.



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