Hall's identity

In mathematics, Hall's identity may be:

• The Hall–Witt identity $[x,y^{-1},z{]}^y\cdot [y,z^{-1},x{]}^z\cdot [z,x^{-1},y{]}^x=1$
• The Hall identity [ [x,y]²,z] = 0 for 2 by 2 matrices, showing that this is a polynomial identity ring
• The Hall–Petresco identity for groups expressing x^my^m in terms of powers of elements of the descending central series.

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