this is for holding javascript data
Michela Ceria edited bits3.tex
over 7 years ago
Commit id: 20baaa19e201f245da7c8fe3327bf6f64b251099
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diff --git a/bits3.tex b/bits3.tex
index ab08014..86eaa21 100644
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\end{center}
\end{Example}
\begin{Example}\label{Buffo}
Let us consider a polynomial which is \emph{not} of the form $f=x^n+\ldots+1$, i.e. $f=x^3+x^2$, using it to construct a LFSR.
\\
We take the following initial state
\begin{center}
\begin{tabular}{ |c ||c|| c | c | c |}
\hline
? & $\longrightarrow \longrightarrow$ & 0&1 & 1 \\
\hline
\end{tabular}
\end{center}
and we take the bit in the position represented by $x^2$, i.e. $0$ as mysterious bit:
\begin{center}
\begin{tabular}{ |c ||c|| c | c | c |}
\hline
0 & $\longrightarrow \longrightarrow$ & 0&1 & 1 \\
\hline
\end{tabular}
\end{center}
After a shift to the right, we obtain
\begin{center}
\begin{tabular}{ |c ||c|| c | c | c |}
\hline
? & $\longrightarrow \longrightarrow$ & 0&0 & 1 \\
\hline
\end{tabular}
\end{center}
The mysterious bit turns out to be $0$ again, so we have
\begin{center}
\begin{tabular}{ |c ||c|| c | c | c |}
\hline
0 & $\longrightarrow \longrightarrow$ & 0&0 & 1 \\
\hline
\end{tabular}
\end{center}
and, after a shift to the right, we get
\begin{center}
\begin{tabular}{ |c ||c|| c | c | c |}
\hline
? & $\longrightarrow \longrightarrow$ & 0& 0 & 0 \\
\hline
\end{tabular}
\end{center}
From now on, we are stuck; indeed the mysterious bit will always be equal to $0$ and so, after the shift to the right, we will always obtain $(0,0,0)$
\end{Example}
\begin{Theorem}
If $p\in \Fb[x]$ is primitive then is irreducible.
\end{Theorem}