john_hopes's blog

By john_hopes, history, 13 months ago, In English,

Suppose, I know m1, m2, m3 and P1, P2, P3 of the following equations. Here P1, P2, P3 are prime numbers.

X mod P1 = m1

X mod P2 = m2

X mod P3 = m3

Now, for another prime number P4,

I need to find, X mod P4 = ?

Using Chinese Remainder Theorem I can calculate this if P4 is not a prime and is equal to (P1xP2xP3).

How can I solve this problem for any prime P4?

 
 
 
 
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13 months ago, # |
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Just find X from the three equations, and calculate X mod P4? I assume it's given to you.

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13 months ago, # |
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If P4 is different from P1, P2 and P3, then (by the Chinese Remainder Theorem) X mod P4 can be anything, as you can solve the 4-equation system regardless of the value you choose for X mod P4.