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Basically what we're going 
to talk about in this video is

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the ring Z m. That's our

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key, key, key feature 
in this presentation.

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But to get there, I'm going 
to define a couple of…

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what’s the word…a couple of 
concepts in abstract algebra.

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I'm going to describe 
Congruence Classes, I'm going to

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describe the concept 
of being well-defined,

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this is a very important 
notion in algebra

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and it extends to many fields,

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and then we're going to 
finish off with a couple of

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tables. An addition table 
and a multiplication table for

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for the integers modulo 4.