# Differences

This shows you the differences between two versions of the page.

frames [2010/07/29 15:46] (current)
Line 1: Line 1:
+=====Frames=====
+
+Abbreviation: **Frm**
+
+====Definition====
+A \emph{frame} is a structure $\mathbf{A}=\langle A, \bigvee, \wedge, e, 0\rangle$ of type $\langle\infty, 2, 0, 0\rangle$ such that
+
+$\langle A, \bigvee, 0\rangle$ is a [[complete semilattice]] with $0=\bigvee\emptyset$,
+
+$\langle A, \wedge, e\rangle$ is a [[meet semilattice with identity]], and
+
+$\wedge$ distributes over $\bigvee$:  $x\wedge(\bigvee Y)=\bigvee_{y\in Y}(x\wedge y)$
+
+Remark: This is a template.
+
+It is not unusual to give several (equivalent) definitions. Ideally, one of the definitions would give an irredundant axiomatization that does not refer to other classes.
+
+==Morphisms==
+Let $\mathbf{A}$ and $\mathbf{B}$ be frames. A morphism from $\mathbf{A}$ to $\mathbf{B}$ is a function $h:A\rightarrow B$ that is a homomorphism:
+$h(\bigvee X)=\bigvee h[X]$ for all $X\subseteq A$ (hence $h(0)=0$),
+$h(x \wedge y)=h(x) \wedge h(y)$ and
+$h(e)=e$.
+
+====Definition====
+A \emph{...} is a structure $\mathbf{A}=\langle A,...\rangle$ of type $\langle +...\rangle$ such that
+
+$...$ is ...:  $axiom$
+
+$...$ is ...:  $axiom$
+
+====Examples====
+Example 1:
+
+====Basic results====
+
+
+====Properties====
+Feel free to add or delete properties from this list. The list below may contain properties that are not relevant to the class that is being described.
+
+^[[Classtype]]                        |(value, see description) [(Ln19xx)]  |
+^[[Equational theory]]                | |
+^[[Quasiequational theory]]           | |
+^[[First-order theory]]               | |
+^[[Locally finite]]                   | |
+^[[Residual size]]                    | |
+^[[Congruence distributive]]          | |
+^[[Congruence modular]]               | |
+^[[Congruence $n$-permutable]]        | |
+^[[Congruence regular]]               | |
+^[[Congruence uniform]]               | |
+^[[Congruence extension property]]    | |
+^[[Definable principal congruences]]  | |
+^[[Equationally def. pr. cong.]]      | |
+^[[Amalgamation property]]            | |
+^[[Strong amalgamation property]]     | |
+  Epimorphisms are surjective     &no \\\hline
+
+====Finite members====
+
+$\begin{array}{lr} + f(1)= &1\\ + f(2)= &\\ + f(3)= &\\ + f(4)= &\\ + f(5)= &\\ +\end{array}$
+$\begin{array}{lr} + f(6)= &\\ + f(7)= &\\ + f(8)= &\\ + f(9)= &\\ + f(10)= &\\ +\end{array}$
+
+
+====Subclasses====
+  [[...]] subvariety
+
+  [[...]] expansion
+
+
+====Superclasses====
+  [[...]] supervariety
+
+  [[...]] subreduct
+
+
+====References====
+
+[(Ln19xx>
+F. Lastname, \emph{Title}, Journal, \textbf{1}, 23--45 [[MRreview]]
+)]
+
+