an i/o behavior L consists of:
a time set K;
a nonempty set J called the control-value or input-value space of J;
a nonempty set H called the output-value or measurement-value space of H; and
a map G called the response map of G, which is defined on a nonempty subset G of G, such that the following property holds:
restriction
if F is in F, then also F for each F.