* %$F_{k-1} = F_{k+1} - F_k$%; in particular, %$F_{-1} = 1$% and
* %$F_{-2} = -1$%.) We say that %$F_k$% is the %$k$%th Fibonacci number.
*
- * We work in the ring %$\ZZ[t]/(t^2 - t -1)$%. Every residue class in this
+ * We work in the ring %$\ZZ[t]/(t^2 - t - 1)$%. Every residue class in this
* ring contains a unique representative with degree at most 1. I claim that
* %$t^k = F_k t + F_{k-1}$% for all %$k$%. Certainly %$t = F_1 t + F_0$%.
* Note that %$t (F_{-1} t + F_{-2}) = t (t - 1) = t^2 - t = 1$%, so the