Problem from China Olympiad
What does the capital C symbol mean?
[Math] What does this C symbol mean
combinatoricselementary-set-theorynotation
combinatoricselementary-set-theorynotation
Problem from China Olympiad
What does the capital C symbol mean?
Best Answer
It is the binomial coefficient. There are 3 ways to write it in China:
In mainland, we prefer $$C_n^r=\frac{n!}{r!(n-r)!}.$$
In Hong Kong, we prefer $$nCr=C_r^n=\frac{n!}{r!(n-r)!}.$$
All are acceptable.