TOPICS
Search

Chinese Remainder Theorem


The Chinese remainder theorem states that if m_1 and m_2 are positive integers which are relatively prime and a_1 and a_2 are any two integers, then there is an integer x such that

 x=a_1 (mod m_1)
(1)

and

 x=a_2 (mod m_2).
(2)

Moreover, x is uniquely determined modulo m_1m_2. Equivalently, every pair of residue classes modulo m_1 and m_2 corresponds to a unique residue class modulo m_1m_2.

The Chinese remainder theorem is implemented in the Wolfram Language as ChineseRemainder[{a1, a2, ...}, {m1, m2, ...}]. It is also implemented indirectly using Reduce with a domain specification of Integers.

More generally, given simultaneous congruences

 x=a_i (mod m_i)
(3)

for i=1, ..., r, where the m_i are pairwise relatively prime positive integers, a solution is

 x=a_1b_1M/(m_1)+...+a_rb_rM/(m_r) (mod M),
(4)

where

 M=m_1m_2...m_r
(5)

and the b_i are determined from

 b_iM/(m_i)=1 (mod m_i).
(6)

See also

Congruence, Congruence Equation, Linear Congruence Equation

Explore with Wolfram|Alpha

References

Flannery, S. and Flannery, D. In Code: A Mathematical Journey. London, England: Profile Books, pp. 123-125, 2000.Ireland, K. and Rosen, M. "The Chinese Remainder Theorem." §3.4 in A Classical Introduction to Modern Number Theory, 2nd ed. New York: Springer-Verlag, pp. 34-38, 1990.Numberphile. "Chinese Remainder Theorem and Cards." Aug. 8, 2018. https://www.youtube.com/watch?v=l9dXo5f3zDc.Séroul, R. "The Chinese Remainder Theorem." §2.6 in Programming for Mathematicians. Berlin, Germany: Springer-Verlag, pp. 12-14, 2000.Uspensky, J. V. and Heaslet, M. A. Elementary Number Theory. New York: McGraw-Hill, pp. 189-191, 1939.Wagon, S. "The Chinese Remainder Theorem." §8.4 in Mathematica in Action. New York: W. H. Freeman, pp. 260-263, 1991.

Referenced on Wolfram|Alpha

Chinese Remainder Theorem

Cite this as:

Weisstein, Eric W. "Chinese Remainder Theorem." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/ChineseRemainderTheorem.html

Subject classifications