: We consider a class of tridiagonal operators induced by not necessary pseudoergodic biinfinite sequences. Using only elementary techniques we prove that the numerical range of such operators is contained in the convex hull of the union of the numerical ranges of the operators corresponding to the constant biinfinite sequences; whilst the other inclusion is shown to hold when the constant sequences belong to the subshift generated by the given biinfinite sequence. Applying recent results by S. N. Chandler-Wilde et al. and R. Hagger, which rely on limit operator techniques, we are able to provide more general results although the closure of the numerical range needs to be taken.

Resumen. Se muestra cómo, mediante el uso de una sola capa de neuronas pulsantes, más aún con una sola neurona, es posible hacer la clasificación de patrones, ya sea de una función binaria como la función XOR o bien de una base de datos con decenas de características. Se ocupa el modelo de Izhikevich para modelar el comportamiento de las neuronas pulsantes utilizadas. Principalmente se pretende explotar el uso de una sola neurona para lograr realizar clasificación, analizando el posible alcance. Los resultados obtenidos son alentadores.Abstract. It is shown how, through the use of a single layer of spiking neurons, even more so with a single neuron, it is possible to make the classification of patterns, either a binary function as the XOR function or a database with tens of characteristics. Izhikevich model is used for modeling the behavior of the used spiking neurons. Mainly intends to exploit the use of a single neuron to perform classification, analyzing the possible scope. Obtained results are encouraging.