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Spain Contests
Spain Mathematical Olympiad
1969 Spain Mathematical Olympiad
8
8
Part of
1969 Spain Mathematical Olympiad
Problems
(1)
periodic replacements of wheels
Source: Spanish Mathematical Olympiad 1969 P8
12/5/2022
The house SEAT recommends to the users, for the correct conservation of the wheels, periodic replacements of the same in the form
R
→
3
→
2
→
1
→
4
→
R
R \to 3 \to 2 \to 1 \to 4 \to R
R
→
3
→
2
→
1
→
4
→
R
, according to the numbering of the figure. Calling
G
G
G
to this change of wheels,
G
2
=
G
G
G^2 = GG
G
2
=
GG
to making this change twice, and so on for the other powers of
G
G
G
, a) Show that the set of these powers forms a group, and study it. b) Each puncture of one of the wheels is also equivalent to a substitution in which said wheel is replaced by the spare one
(
R
)
(R)
(
R
)
and, once repaired, it comes to occupy the place of this obtained
G
G
G
as a product of prick transformations. Do they form a group? https://cdn.artofproblemsolving.com/attachments/4/a/712fede88321c67753417fda828a08ba528b4f.png
combinatorics