Sunday, January 15, 2017

January 15, 2017 Sunday

Bedtime Story 

Peano axioms


Second-order logic or the propositional logic is an extension of the first-order logic that uses quantifiers both for variables and relationships.

Second-order logic has variables and quantifiers not only for individuals but also for subsets of the universe.

It is not easy for me explain second-order logic further than this though the last axiom is an example of that.

Now let me list out the nine axioms of Peano:

1. 0 is a natural number.

2. For every natural number x, x = x. (Reflexive relationship)

3. For all natural numbers x and y, if x = y, then y = x. (Symmetric relationship)

4. For all natural numbers x, y and z, if x = y and y = z,
then x = z. (Transitive relationship)

5. For all a and b, if b is a natural number and a = b, then a is also a natural number.

6. For every natural number n, S(n) is a natural number.

7. For all natural numbers m and n, m = n, if and only if,
S(m) = S(n). (Injective function)

8. For every natural number n, S(n) = 0 is false.

(In other words, there is no natural number whose successor is 0)
9. If K is a set such that:

0 is in K and

For every natural number n, n being in K implies that S(n) is in K,

Then K contains every natural number.

This last axiom is known as the axiom of induction and is an example of second-order logic.

This axiom of induction is most interesting one and needs some more investigation.

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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