Correction to: Foundations of Science https://doi.org/10.1007/s10699-021-09827-9


In Sect.  3.2.6., in the first paragraph after Eqs. (31) the following sentence:


“where the “cyclical components” …”


must be replaced by


“where the “trend” and the “cyclical components” …”


In Sect. 3.2.6., in the paragraph:


“Nevertheless, there is a main drawback in Zambelli’s procedure: he did not normalize the coefficients aj, bj and cj. In other words, in the above expression (32) of x(t), Zambelli posed \({a}_{0}={a}_{1}={a}_{2}={a}_{3}=1\).”


The last sentence must be replaced by:


“In other words, in the above expression (32) of x(t), Zambelli posed \({a}_{1}={a}_{2}={a}_{3}=1\).”


In Sect. 3.2.6., in the paragraph after Fig. 6 the following sentence:


“Unfortunately, it does not seem that Zambelli has taken into account such normalization since in his case \({a}_{0}+{a}_{1}+{a}_{2}+{a}_{3}=4\)


must be replaced by


“Unfortunately, it does not seem that Zambelli has taken into account such normalization since in his case \({a}_{1}+{a}_{2}+{a}_{3}=3\)”.


The following sentence:


“This solution x(t) has been plotted in Fig. 6 below with the following parameters: \({a}_{0}=0.01, {a}_{1}=0.1, {a}_{2}=0.2, {a}_{3}=0.699\), the sum of which is obviously equal to unity, as recommended by Frisch”.


must be replaced by:


“This solution x(t) has been plotted in Fig. 6 below with the following parameters: \({a}_{1}=1, {a}_{2}=+30, {a}_{3}=-30\), the sum of which is obviously equal to unity, as recommended by Frisch”.


So Fig. 6 may be replaced by the following one:

Fig. 6
figure 1

Solution x(t) of Frisch’s system (11), i.e., of MODEL 2