[Jprogramming] A permutation and it's inverse.

[peter at easthope.ca]

Hello again,

To my understanding an example of the usual representation of a 
permutation is 3 2 4 1, meaning the permutation takes 3 to 1, 2 to 2, 
4 to 3 and 1 to 4. The inverse is 4 2 1 3.  OK?

In J,
what is a function producing the inverse of a permutation?
what is a function composing two permutations into one?

Thanks,                 ... Peter E.





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