Proving Abelian Group Structure in C^A

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The discussion focuses on proving the Abelian group structure in C^A, emphasizing the need to demonstrate closure, identity, and inverses. It suggests that since C is a ring and thus an Abelian group, one can leverage its properties to show associativity and commutativity for function multiplication. The importance of identifying the identity element and ensuring the existence of inverses for each function is highlighted. Additionally, the necessity of proving that the product of functions remains within C^A is mentioned, along with a query about the concept of A-hat and group homomorphisms. Overall, the thread seeks clarity on establishing the group structure and related properties.
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Homework Statement



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Homework Equations





The Attempt at a Solution



For the first question, since [f(a)][g(a)] is in C, can I just say that since C is a ring, it is an abelian group, then the four axioms are proven? Then just show closure? Probably not I'm guessing. Associativity of multiplying functions seems so fundamental to me that I really don't know what to do...

For the second question, shall I start by using composition of functions and then the properties of composition of a function and its inverse, and then go on about the identity function?
 

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I'd say question one is asking you to flesh out the group structure.

1. What's the identity element? (make sure it's a member of C^A).

2. For each element f, what's the inverse element? (make sure it's well defined
- namely, why can you find f^-1 for each f? )

Closure is trivial but should be mentioned, namely why is (fg) a well
defined member of C^A when f and g are?

Associativity (and Abelian-ness) of course follow from the properties of C,
but you should have a proof showing f(gh) =(fg)h.

For question 2. I don't know what A-hat is. What do you know
about group homomorphisms at this point?
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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