What Does Reduced Modulo N mean in this context?

1. What is a unit modulo n?
2. What do you call the N in modulo congruence?
3. How do you read congruent modulo n?

What is a unit modulo n?

Hence another name is the group of primitive residue classes modulo n. In the theory of rings, a branch of abstract algebra, it is described as the group of units of the ring of integers modulo n. Here units refers to elements with a multiplicative inverse, which, in this ring, are exactly those coprime to n.

What do you call the N in modulo congruence?

Congruence. Given an integer n > 1, called a modulus, two integers a and b are said to be congruent modulo n, if n is a divisor of their difference (that is, if there is an integer k such that a − b = kn).

How do you read congruent modulo n?

We say integers a and b are "congruent modulo n" if their difference is a multiple of n. For example, 17 and 5 are congruent modulo 3 because 17 - 5 = 12 = 4⋅3, and 184 and 51 are congruent modulo 19 since 184 - 51 = 133 = 7⋅19.