In title, $F$ denotes a field. Does knowing the trace of two matrices and their product specify those two matrices? Up to some equivalence, perhaps?
2026-03-31 14:28:20.1774967300
For any $A, B \in SL(2, F)$, does knowing $\operatorname{tr}A$, $\operatorname{tr}B$, and $\operatorname{tr}AB$ specify $A$ and $B$?
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You could replace $A$ and $B$ with conjugates $CAC^{-1}$ and $CBC^{-1}$, with the effect of replacing $AB$ with $CABC^{-1}$, so none of the traces change. So at best you could specify $A,B$ only up to conjugacy in this manner.