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Discrete Math - Modular Arithmetic

by hammonjj
Tags: arithmetic, discrete, math, modular
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hammonjj
#1
Jul1-12, 03:48 PM
P: 33
1. The problem statement, all variables and given/known data
For which values of n≥2 does the implication:

axb=0 ⇔ a=0 or b=0

For some Zn (n should be a subscript)

NOTE: For the a x b, the x should be the x that has a circle around it. I didn't see that symbol in the "quick symbols" :)

2. Relevant equations
I know that this is true when n is a prime (answer in back of book), but I don't understand why. For example, if a=5 and b = 4, then that would also be 0 for n=5, right? Do I just not understand how to do modular arithmetic?

Thanks!
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HallsofIvy
#2
Jul1-12, 05:39 PM
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PF Gold
P: 39,353
What is your definition of that symbol? I would have interpreted as a "tensor product" but that doesn't really make sense here. I suspect it is a "special operation" your text is defining for this problem.
tiny-tim
#3
Jul1-12, 05:42 PM
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tiny-tim's Avatar
P: 26,157
hi hammonjj!
Quote Quote by hammonjj View Post
For which values of n≥2 does the implication:

axb=0 ⇔ a=0 or b=0

I know that this is true when n is a prime (answer in back of book), but I don't understand why. For example, if a=5 and b = 4, then that would also be 0 for n=5, right?
ah, but 5 = 0


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