Modular arithmetic in matrices

nahuel_pelado

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Jul 17, 2010
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This is the question: What must fulfill a matrix to be invertible in module Zn? Demonstrate. Z refers to integers.

I really appreciate that someone could help me with this because i couldn't find strong information about it.
I think that considering A as a matrix... the det(A) must be coprime with the module (n), so that gcd(det(A),n)=1 but i'm not sure about it.

In case that a matrix has inverse in module Zn, is correct to use this to verify?: A.A^-1 mod n = A^-1.A mod n = I ... I = identity matrix
 
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