Library / Lie Groups and Lie Algebras / Chapter II / § 2
Example
Tag 0A3G, permanent. Cite it as [Bourbaki, Tag 0A3G].
Lie Groups and Lie Algebras, chapter II, § 2. Free Lie algebras
Suppose that X X X has two elements x , y x, y x , y ; let X X X be ordered such that x < y x < y x < y . The construction given in the proof of Proposition 11 gives a set H H H with 14 elements of length ≤ 5 \leq 5 ≤ 5 given in the following table:
H 1 w 1 = x H 2 w 3 = ( x y ) H 3 w 4 = ( x ( x y ) ) w 5 = ( y ( x y ) ) H 4 w 6 = ( x ( x ( x y ) ) ) ) w 7 = ( y ( x ( x y ) ) ) ) w 8 = ( y ( y ( x y ) ) ) ) H 5 w 9 = ( x ( x ( x ( x y ) ) ) ) w 10 = ( y ( x ( x ( x y ) ) ) ) w 11 = ( y ( y ( x ( x y ) ) ) ) ) w 12 = ( y ( y ( y ( x y ) ) ) ) w 13 = ( ( x y ) ( x ( x y ) ) ) w 14 = ( ( x y ) ( y ( x y ) ) ) .
\begin{array}{cccc}
H_1 & w_1 = x \\
H_2 & w_3 = (xy) \\
H_3 & w_4 = (x(xy)) & w_5 = (y(xy)) \\
H_4 & w_6 = (x(x(xy)))) & w_7 = (y(x(xy)))) & w_8 = (y(y(xy)))) \\
H_5 & w_9 = (x(x(x(xy)))) & w_{10} = (y(x(x(xy)))) & w_{11} = (y(y(x(xy))))) \\
& w_{12} = (y(y(y(xy)))) & w_{13} = ((xy)(x(xy))) & w_{14} = ((xy)(y(xy))).
\end{array}
H 1 H 2 H 3 H 4 H 5 w 1 = x w 3 = ( x y ) w 4 = ( x ( x y )) w 6 = ( x ( x ( x y )))) w 9 = ( x ( x ( x ( x y )))) w 12 = ( y ( y ( y ( x y )))) w 5 = ( y ( x y )) w 7 = ( y ( x ( x y )))) w 10 = ( y ( x ( x ( x y )))) w 13 = (( x y ) ( x ( x y ))) w 8 = ( y ( y ( x y )))) w 11 = ( y ( y ( x ( x y ))))) w 14 = (( x y ) ( y ( x y ))) .
(The elements of H H H have been numbered according to the total ordering chosen on each H n H_n H n .)
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.
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Transcribed from the printed volume. Not translated.