Figure 1: Partitions in a Parameter Space with Small a1, 1, Small a1, 3 |
I have been exploring patitions of parameter spaces by fluke switch points. I always have trouble visualizing higher dimensional spaces. Sometimes, my examples are two-dimensional. If I were doing more formal mathematics, instead of numerical exploration, I would not need to care.
This post is a continuation of the example developed here, here, and here. I present two-dimensional slices of a four-dimensional space.
2.0 Perturbations of Coefficients of ProductionAs the result of technical change, coefficients of production vary. No variation in labor coefficients or of the output matrix are considered here so as to retain reverse labor substitution at the switch point between Beta and Delta and forward substitution of labor at the switch points between Alpha and Gamma and between Gamma and Delta. Accordingly, consider perturbations of the coefficients of production in the first row of the input matrix. These parameters define a four-dimensional space. How does the analysis of the choice of technique vary with a decrease in these coefficients? The recurrence of truncation turns out be only a transient possibility in secular time with this specific model of technical change. The reverse substitution of labor can occur without the recurrence of truncation, but is also transient. Capital reversing, also transient, occurs in one region of parameter space.
2.1 Small Amounts of Circulating Capital Needed for New MachinesThe parameter space is partitioned by parameters corresponding to fluke switch points. Figure 1 shows partitions with the values of a1,1 and a1,3 as in this previous post. A switch point is a fluke if it is a knife edge case in which almost all perturbations of model parameters destroy its defining properties. Four of the five partitions shown correspond to a switch point on the axis for the rate of profits. With four techniques, switch points between six pairs are possible. A switch point between Alpha and Delta can only occur as an intersection of all four curves. The same goes for a switch point between Beta and Gamma. These two pairs of techniques correspond to the partition for the switch point at which all four wage curves intersect, called here a four-technique pattern.
The sequence of techniques along the wage frontier is invariant in each numbered region. Table 1 lists the cost-minimizing techniques in each region, in order of an increasing rate of profits. Consider perturbations of the coefficients of production, a1,2 and a1,4, that specify the inputs of corn needed for each process in which the machine is run for the second year of its life. In region 1, to the northeast, old machines require so much circulating capital to operate that it is never cost-minimizing to run them for a second year. The Alpha technique is cost-minimizing, whatever the distribution of income. An improvement in the efficiency of old machines in using circulating capital in the machine industry leads to machines being operated for two years in that industry at large rates of profits, as in region 5. A similar improvement in the efficiency of old machines in the corn industry leads to machines being operated for two years in the corn industry, as in region 2. The recurrence of truncation only occurs in region 4.
Region | Techniques | Notes |
1 | Alpha | No switch point. |
2 | Alpha, Gamma | Lower rate of profits associated with truncation in corn industry, greater output per worker. |
3 | Alpha, Gamma, Delta | Lower rate of profits associated with truncation, greater output per worker. |
4 | Alpha, Gamma, Delta, Beta | Recurrence of truncation in corn industry. |
5 | Alpha, Beta | Lower rate of profits associated with truncation in machine industry, greater output per worker. |
6 | Gamma, Delta | Lower rate of profits associated with truncation in machine industry, greater output per worker. |
7 | Gamma | No switch point. |
8 | Beta | No switch point. |
9 | Delta | No switch point. |
10 | Delta, Beta | Lower rate of profits associated with extension of economic life in corn industry, reverse substitution of labor. |
11 | Gamma, Delta, Beta | Lower rate of profits associated with truncation in machine industry, extension of economic life in corn industry, reverse substitution of labor. |
12 | Alpha, Beta, Delta | Around the Beta vs. Delta switch point, lower rate of profits associated with truncation, smaller output per worker. |
13 | Alpha, Beta, Delta | Lower rate of profits associated with truncation, greater output per worker. |
Figure 2 shows the partitions in the parameter space at a higher level of a1,3. The structure in Figure 1 has moved upwards and to the left. The wedge in which the recurrence of truncation appears, region 4, has widened a bit. A new partition has appeared, for a fluke switch point between Gamma and Delta on the wage axis. For parameters where the partitions between regions 2 and 3 and between regions 2 and 7 intersect, the wage frontier has fluke switch points on both the wage axis and the axis for the rate of profits. For a low enough value of a1,4, it is no longer cost-minimizing to truncate the machine in both industries at a low rate of profits. Gamma is cost-minimizing, whatever the distribution of income, for a high enough value of a1,2 and a low enough value of a1,4.
Figure 2: Parameter Space with Small a1, 1, Large a1, 3 |
2.3 Large Amounts of Circulating Capital Needed for New Machines in the Machine Industry
Figure 3 shows the partitions in the parameter space at a higher level of a1,1. The amount of corn needed to operate a new machine in the corn industry, a1,3, is the same as in Figure 1. Only the partitions and regions to the right are labeled in the figure. This part of the parameter space resembles those slices examined above, with a couple of variations. To the right, the lower boundary of region 5 corresponds to a switch point on the axis for the rate of profits, not a fluke switch point in which all four wage curves intersect. The upper boundary of region 3 now is, to the right, such a four-technique pattern of switch points.
Figure 3: Parameter Space with Large a1, 1, Small a1, 3 |
Figure 4 is an enlargement of the lower left of this slice of the parameter space. Three new points that are a fluke in multiple ways have appeared. One point corresponds to the intersection of the four wage curves on the wage axis. This point is the intersection of five partitions in the parameter space, just as the point in parameter space corresponding to the intersection of the four wage curves on the axis for the rate of profits. The region in which the recurrence of truncation occurs, region 4, has appeared. The reverse substitution of labor also occurs in regions 10 and 11. Two points in the part of the parameter space depicted correspond to fluke switch points simultaneously lying on both axes.
Figure 4: Parameter Space with Large a1, 1, Small a1, 3 (Enlarged) |
Figure 5 enlarges this slice of the parameter space in the middle of Figure 3. The sequence of cost-minimizing techniques, in order of an increasing rate of profits, is Alpha, Beta, and Delta in both region 12 and region 13. The boundary between regions 12 and 13 corresponds to an intersection of the Beta and Delta wage curves on the waxis but not on the frontier. In region 12, the wage curves for Beta and Delta intersect twice in the first quadrant. The second intersection is on the frontier. It is a switch point exhibiting capital-reversing. Around the switch point between Beta and Delta a lower rate of profits is associated with a decreased capital-intensity and decreased net output per worker in the economy as a whole.
Figure 5: Parameter Space with Large a1, 1, Small a1, 3 (Another Enlargement) |
3.0 Conclusion
The exploration of partitions in parameter space supports an analysis of technical change in which the circulating capital needed to operate a machine decreases. A trajectory from the upper right to the lower left in the figures and from Figures 2 or 3 to Figure 1 represent this specific form of technical change.
This analysis illustrates how perturbing coefficients of production affects the analysis of the choice of technique. Parameter spaces are partitioned by fluke switch points into regions in which the variation of the cost-minimizing technique with distribution is itself invariant. Some of the structures formed by intersections of partitions are not specific to the example, or even to models of fixed capital. For example, fluke switch points can arise in many models simultaneously on both the wage axis and the axis for the rate of profits. Perturbations of parameters around such a point eliminates or creates the possibility for certain techniques to be cost-minimizing at extreme ranges for the rate of profits.
Likewise, perturbation analysis supports the analysis of specific forms of technical progress. By contrast with fluke switch points, the recurrence of truncation, the reverse substitution of labor, and capital-reversing are not flukes. The reverse substitution of labor occurs in regions in which the recurrence of truncation does not occur. In this sense, the reverse substitution of labor is more general in this example. Capital-reversing arises in a region in which neither of these other 'perverse' phenomena occur. Configurations of parameters in which these phenomena arise, however, define only a few regions of the parameter space. This observation seems capable of generalization to other 'perverse' phenomena in other examples. Other forms of technical progress can be explored.