Mathematical Structures: Semirings with identity and zero

# Semirings with identity and zero

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http://mathcs.chapman.edu/structuresold/files/Semirings_with_identity_and_zero.pdf
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\begin{document}
\textbf{\Large Semirings with identity and zero}
\quad\href{http://math.chapman.edu/cgi-bin/structures?action=edit;id=Semirings_with_identity_and_zero}{edit}

\abbreviation{SRng$_{01}$}

\begin{definition}
A \emph{semiring with identity and zero} is a structure $\mathbf{S}=\langle S,+,0,\cdot,1 \rangle$ of type $\langle 2,0,2,0\rangle$ such that

$\langle S,+,0\rangle$ is a \href{Commutative_monoids.pdf}{commutative monoids}

$\langle S,\cdot,1\rangle$ is a \href{Monoids.pdf}{monoids}

$0$ is a zero for $\cdot$:  $0\cdot x=0$, $x\cdot 0=0$

$\cdot$ distributes over $+$:  $x\cdot(y+z)=x\cdot y+x\cdot z$, $(y+z)\cdot x=y\cdot x+z\cdot x$
\end{definition}

\begin{morphisms}
Let $\mathbf{S}$ and $\mathbf{T}$ be semirings with identity and zero. A morphism from $\mathbf{S}$
to $\mathbf{T}$ is a function $h:S\rightarrow T$ that is a homomorphism:

$h(x+y)=h(x)+h(y)$, $h(x\cdot y)=h(x)\cdot h(y)$, $h(0)=0$, $h(1)=1$
\end{morphisms}

\begin{basic_results}
\end{basic_results}
\begin{examples}
\begin{example}
\end{example}
\end{examples}
\begin{table}[h]
\begin{properties} (\href{http://math.chapman.edu/cgi-bin/structures?Properties}{description})

\begin{tabular}{|ll|}\hline
Classtype & variety\\\hline
Equational theory & decidable\\\hline
Quasiequational theory & \\\hline
First-order theory & undecidable\\\hline
Locally finite & no\\\hline
Residual size & unbounded\\\hline
Congruence distributive & no\\\hline
Congruence modular & no\\\hline
Congruence n-permutable & \\\hline
Congruence regular & \\\hline
Congruence uniform & \\\hline
Congruence extension property & \\\hline
Definable principal congruences & \\\hline
Equationally def. pr. cong. & \\\hline
Amalgamation property & \\\hline
Strong amalgamation property & \\\hline
Epimorphisms are surjective & \\\hline
\end{tabular}
\end{properties}
\end{table}
\begin{finite_members} $f(n)=$ number of members of size $n$.

$\begin{array}{lr} f(1)= &1\\ f(2)= &1\\ f(3)= &\\ f(4)= &\\ f(5)= &\\ f(6)= &\\ \end{array}$
\end{finite_members}
\hyperbaseurl{http://math.chapman.edu/structures/files/}
\parskip0pt
\begin{subclasses}\

\href{Idempotent_semirings_with_identity_and_zero.pdf}{Idempotent semirings with identity and zero}

\href{Rings_with_identity.pdf}{Rings with identity}

\end{subclasses}
\begin{superclasses}\

\href{Semirings_with_zero.pdf}{Semirings with zero}

\href{Semirings_with_identity.pdf}{Semirings with identity}

\end{superclasses}

\begin{thebibliography}{10}

\bibitem{Ln19xx}

\end{thebibliography}

\end{document}
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Last edited July 10, 2004 11:04 am by Jipsen (diff)
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