Sunday, February 19, 2017

February 19, 2017 Sunday

Bedtime Story 


Computable Functions


A computable function is that wherein a well-defined algorithm exists that can with precisely defined set of steps that can compute the output of a function from all the elements of its input.

In even more simple terms, if there exists a finite procedure or an algorithm to compute a given function, then that function is computable.

Herbert Enderton, a professor of mathematics at UCLA (now deceased) has given the following three characteristics of the procedure or the algorithm that applied to computable functions:

1. The algorithm or the procedure should work for a large number of arguments (in the mathematical sense). (There is no limit to the number of arguments that is applicable).

2. The procedure is supposed to halt after a finite number of steps to produce an output. (Again, there is no limit to the number of steps needed to produce that output nor any time constraint).

3. There is no limit to the amount of storage space that could be needed to compute a function.

Besides these 3, there are some other interesting caveats about computable functions.

If the input argument does not happen to fall in the domain of the function, then it never halts or it gets stuck.

There is no need for any device that is carrying out the computable function to check the correctness of the result since it is assumed that if there is an output, it must be correct as the sanctity of the algorithm is never a suspect.

Mathematicians and logicians have their own technical way of writing down a computable function.

It is interesting and not complicated and hence it is worth mentioning it.

A function f:N k→N is computable if and only if there is an effective procedure that, given any k-tuple x of natural numbers, will produce the value f(x).

Now I will need to tell you about tuple.

In mathematics, a tuple is a list of finite ordered (in sequence) elements.

A n-tuple is an ordered list of n elements where n is a non-negative integer.

So a 0-tuple is an empty on a null tuple.

A sequence such as (5, 10, 15, 20, 25) would be a 5-tuple.

So now let us go back and search for the first such computable function.

Stay tuned to the voice of an average story storytelling chimpanzee or login at http://panarrans.blogspot.in/
                              
Good night mon ami and my fellow cousin ape.
                   
  
                

             












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Another great educator and a teacher that I am aware of is Professor Subhashish Chattopadhyay in Bangalore, India.

While I narrate stories, Professor Subhashish an electronic engineer and a former professor at BARC, does and teaches real mathematics and physics.

He started the participation of Indian students at the International Physics Olympiad.

Do visit him here:


All his books can be downloaded for free through this link:


For edutainment and English education of your children, I recommend this large collection of Halloween Songs for Kids:

https://www.youtube.com/channel/UCd14DRdYKj454znayUIfcAg

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