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15
Inequality in factorials
Inequality in factorials
Source:
September 29, 2010
inequalities
factorial
algebra
combinatorics
combinatorial inequality
IMO Shortlist
IMO Longlist
Problem Statement
(
C
Z
S
4
)
(CZS 4)
(
CZS
4
)
Let
K
1
,
⋯
,
K
n
K_1,\cdots , K_n
K
1
,
⋯
,
K
n
be nonnegative integers. Prove that
K
1
!
K
2
!
⋯
K
n
!
≥
[
K
n
]
!
n
K_1!K_2!\cdots K_n! \ge \left[\frac{K}{n}\right]!^n
K
1
!
K
2
!
⋯
K
n
!
≥
[
n
K
]
!
n
, where
K
=
K
1
+
⋯
+
K
n
K = K_1 + \cdots + K_n
K
=
K
1
+
⋯
+
K
n
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