Chaos in a four-variable piecewise-linear system of differential equations

A set of four piecewise-linear ordinary differential equations in four variables is examined. The system has a single positive Lyapunov characteristic exponent. Over a parameter range, however, the Kaplan-Yorke dimension is greater than three, and the Poincare section appears to have two continuous directions. An example is discussed in which the equations describe a chemical system whose solutions have the same characteristics as the piecewise-linear set as a limiting case