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National and Regional Contests
Russia Contests
Soros Olympiad in Mathematics
VII Soros Olympiad 2000 - 01
11.7
11.7
Part of
VII Soros Olympiad 2000 - 01
Problems
(1)
sets of sequences, M<= 2n-4 (VII Soros Olympiad 2000-01 R1 11.7)
Source:
7/29/2021
Consider all possible functions defined for
x
=
1
,
2
,
.
.
.
,
M
x = 1, 2, ..., M
x
=
1
,
2
,
...
,
M
and taking values
y
=
1
,
2
,
.
.
.
,
n
y = 1, 2, ..., n
y
=
1
,
2
,
...
,
n
. We denote the set of such functions by
T
.
T.
T
.
By
T
0
T_0
T
0
we denote the subset of
T
T
T
consisting of functions whose value changes exactly by
1
1
1
(in one direction or another) when the argument changes by
1
1
1
. Prove that if
M
≥
2
n
−
4
M\ge 2n-4
M
≥
2
n
−
4
, then among the functions from of the set
T
T
T
, there is a function that coincides at least at one point with any function from
T
0
T_0
T
0
. Specify at least one such function. Prove that if
M
<
2
n
−
4
M <2n-4
M
<
2
n
−
4
, then there is no such function.
algebra
Sequence
Sequences