this is for holding javascript data
Michela Ceria edited bits1.tex
about 8 years ago
Commit id: 5f579b57472045f54c9b5fe94592ea2ca113a449
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index e0dd757..d589e45 100644
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...
most of Computer Science applications.
\\
They are represented with the constants $0 $ and $1$ (the two events with the
same probability).
The In Mathematics, the set of
the bits, in Mathematics bits is usually denoted by
%We have the Field of Bits $\Fb$. When we work in Computer Science we often
%consider
...
\caption{Sum and product}\label{SumProd}
\end{table}
The first and second columns represent the values of the input variables $a$ and $b$, the third and the fourth
ones respectively
represent the results of the sum and product of $a$ and
$b$. $b$.\\
Performing operations with bits is not the same as doing so with ``usual''
(real) numbers (from now on, we denote the set of real numbers with $\RR$).
\\
Look
now at third row. We observe
that that, summing the bit $1$ with the bit
$1$ $1$, one gets $0$:
$1+1=0$. $$1+1=0.$$
This also highlights that performing operations with bits is not the same as doing so with ``usual''
(real) numbers.
% indexed
...
% performing operations with bits is not the same as doing so with ``usual''
% (real) numbers.
Anyway, Even if the operations on $\Fb$ are similar but not equals to the corresponding ones on bits, $\Fb$ has very good properties with respect to the operations $+$ and $\cdot$, that are in common with the real
numbers, from now on represented with $\RR$. Indeed, we numbers.
\\
We can observe that $\Fb$ is a \emph{field}, as well as $\RR$ is.
\\
In
particular particular, every element of $\Fb$ has an
opposite \emph{opposite} for the sum,
``+'', ``$+$'', and every element of $\Fb$, that is different from $0$, has an
inverse, \emph{inverse}, exactly as the field of real numbers. For example in the field of real numbers
\[
5+(-5)=0 \mbox{ and } 5\cdot \frac{1}{5}=1.
\]
The notation for In the set
of bits (that - from now on - we will call the \emph{field of bits}), reflects this fact. Indeed, $\Fb$
stands for ``field'' and the subscript $2$ stands for the \emph{size} of the set itself, i.e. the number of its elements. That is we have:
\begin{enumerate}
\item The opposite of $1$ is $1$, in fact $1+1=0$.
\item The opposite of $0$ is $0$, as in $\RR$.
\item The inverse of $1$ is $1$, in fact $1\cdot 1=1$.
\item The inverse of $0$ does not exist as in $\RR$.
\end{enumerate}
The notation for the set of bits (that - from now on - we will call the \emph{field of bits}), reflects this fact. Indeed, $\mathbb{F}$ stands for ``field'' and the subscript $2$ stands for the \emph{size} of the set itself, i.e. the number of its elements.
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