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Formulated 2-Traces

The formulation f(T) of a trace T=t1,...tn over $\Sigma$ is the Boolean function $\lor(\land T (t_i \in T))$ which forms the conjunction of elements of a 2-trace and then disjoins the results. For example, if $T^2_3 (\alpha, \beta,
\gamma) =
\{\{\alpha,\beta\},\{\alpha,\gamma\},\{\beta,\gamma\}\}$ then  
 \begin{displaymath}
f(T^2_3) = (\alpha \land \beta)
\lor (\alpha \land \gamma) \lor (\beta \land \gamma) = 2/3(\alpha, \beta,
\gamma). \end{displaymath} (1)
The significance of formulated traces is that, if a sentence $\alpha$follows classically from every element of a trace T, then $f(T)\rightarrow\alpha$ is a theorem of classical logic.

To illustrate the dependence of least fundamental trace members on n, notice that the least fundamental traces T2n for n = 3, 4 and 5 and inputs $\Sigma =
\{a,b,c,d,e\}$ are:

\begin{displaymath}
T^2_3(a,b,c) = \{\{ab\},\{ac\},\{bc\}\} \end{displaymath}

\begin{displaymath}
T^2_4(a,b,c,d) = \{\{ab\},\{ac\},\{ad\}, \{bcd\}\} \end{displaymath}

\begin{displaymath}
T^2_5(a,b,c,d,e) =
\{\{ab\},\{ac\},\{bcd\}, \{bce\}, \{ade\}\} \end{displaymath}

T2n for any arbitrary n atoms, $\{a,b,c,\cdots,\alpha_n\}$can be expressed as a recursive function  
 \begin{displaymath}
T^2_n =
f(T^2_3)(T^2_{n-1},T^2_{n-2},\alpha_n). \end{displaymath} (2)

Apostoli and Brown prove in [1] that a set of sentences closed under 2/(n + 1) including single elements, contains all formulated n-traces. The question is whether there is an alternative proof of this result that relies upon visualization techniques. A visual approach would help in highlighting features in traces that give rise to large numbers of permutations. An algebraic description of the set of n-traces and a graphic representation would give a precise account of those permutations.


next up previous
Next: Characteristics of truth tables Up: Introduction to Traces Previous: Definition of the n-Trace
Thalie Prevost
11/19/1997