IntelliPaper
Abstract
The practice of the game of chess leads to the development of skills related to memory, logic, concentration, rigor, strategy and the capacity for abstraction. In addition to the benefits observed on learning citizenship, by respecting the rules and others. Solving chess problems is an interesting variation for realizing intellectual development. The common way is to present problems on the chessboard or through diagrams. Here, we present a new method of solving chess problems based on a purely mathematical solution. Concretely, it is a question of solving a chess problem thanks to the solution of equations and the mathematical analysis. Thus with a basic knowledge of mathematics, generally of the secondary level, we can proceed to the resolution with a minimum of knowledge of chess, given that the resolution is done from the algebraic notation of the said problem. Here we advance definitions, properties and theorems.
Also we present here an example of a chess problem solved by the method.
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I. INTRODUCTION
In a pioneering contribution De-Losso et al. (2013) introduced the idea of substituting a single contract by multiple contracts. Specifically, considering a loan of F units of capital, with a term of n periods, at the periodic rate i of compound interest, which has to be reimbursed by periodic constant payments, the usual practice is that the financial institution providing the loan requires the borrower to sign a single contract.
Alternatively, the financial institution may require the borrower to sign n contracts. One for each of the n payments of the single contract. The reason for this procedure is that, considering its cost of capital, the financial institution may have a reduction, in terms of present values, of the amount of taxes it must pay.
In the above-mentioned contribution, it was considered only the usual case of a loan that must be reimbursed by n periodic constant payments. In this paper it will be examined the case where, besides the n periodic payments, the borrower has also to pay a sequence of balloon payments, with periodicity m.
This may be very interesting in the case of Brazil. Since, by law, every employer must pay, to each registered employee, thirteen monthly payments per year. The thirteenth one being known as the "décimo terceiro salário" (the thirteenth wage), which is usually paid during the month of December. As will be shown, the financial institution is also better off if a single contract is substituted by multiple contracts in this new case.
II. THE CASE OF A SINGLE CONTRACT
Suppose that, besides the n constant equal payments p, the borrower has also to pay a sequence of balloon payments. Each one of them with the value P, with periodicity m, where , and the first balloon payment at epoch m.
Denoting by the equivalent rate of compound interest relative to m periods, so that
the assumption of n constant payments with value p, and additional payments with value P, with periodicity equal to m, implies that the following equation must be satisfied:
Therefore, once the value P of the balloon payments has been established, the value p of the n periodic constant payments will be equal to:
Noticing that the payment, , is such that
it follows that, denoting by the outstanding debt at epoch k, just after the payment , by the parcel of interest, and by the corresponding parcel of amortization of , we have:
with and and
As a simple numerical illustration of a single contract, consider the case where , , , , and per period. In this case, the solution of equation (3) implies that, besides the 4 balloon payments of \$ 10,000.00, 12 periodic payments of \$ 5,584.66 will be necessary. Table 1 presents the evolution of debt.
Table 1: Evolution of the debt in the case of a single contract
| k | $J_k$ | $A_k$ | $p_k$ | $S_k$ |
| 0 | 100,000.00 | |||
| 1 | 1,000.00 | 4,584.66 | 5,584,66 | 95,415.34 |
| 2 | 954.15 | 4,630.50 | 5,584,66 | 90,784.84 |
| 3 | 907,85 | 14,676.81 | 15,584,66 | 76,108.03 |
| 4 | 761.08 | 4,823.58 | 5,584,66 | 71,284.45 |
| 5 | 712.84 | 4,871.81 | 5,584,66 | 66,412.64 |
| 6 | 644.13 | 14,920.53 | 15,584,66 | 51,492.11 |
| 7 | 514.92 | 5,069.74 | 5,584,66 | 46,422.37 |
| 8 | 464.22 | 5,120.43 | 5,584,66 | 41,301.94 |
| 9 | 413.02 | 15,171.64 | 15,584,66 | 26,130.30 |
| 10 | 261.30 | 5,323.35 | 5,584,66 | 20,806.94 |
| 11 | 208.07 | 5,376.59 | 5,584,66 | 15,430.35 |
| 12 | 154.30 | 15,430.35 | 15,584,66 | 0.00 |
| $\sum$ | 7,015.89 | 100,000.00 | 107,015.89 |
III. THE CASE OF MULTIPLE CONTRACTS
Instead of a single contract, the financial institution providing the loan has the option of requiring the borrower to sign n individual contracts - one for each of the n payments that would be associated with the case of a single contract. With the value of the loan of the subcontract being the present value, at the same interest rate i, of the payment of the single contract.
That is, the value of the principal of the subcontract, denoted , is:
In this case, the parcel of amortization associated with the payment, denoted as will be:
Namely, the parcel of amortization associated with the subcontract is exactly equal to the value of the loan of the subcontract.
On the other hand, from an accounting point of view, it follows that the parcel of interest associated with the subcontract, which will be denoted by wherein:
It should be especially noted that, although from the strict point of view, not taking into consideration the costs that may be associated with the bookkeeping and registration of the n subcontracts, the total of interest payments is the same in both cases. That is:
However, in terms of present values, and depending on the financial institution cost of capital, it is possible that the financial institution will be better off if it adopts the multiple contracts option. As will be illustrated in the case of our simple example.
Table 2 presents the values of the sequence of payments , the sequence of the parcels of interest in the case of a single contract, and the sequence of the parcels of interest in the case of the adoption of the option of multiple contracts. As well as the sequence of principals and the sequence of amortization components of the subcontracts. Additionally, Table 2 presents also the sequence of differences, , and the sequence of accumulated values of , denoted as , given by:
It is interesting to note that the sequence of the values of has more than one change of sign. However, adapting the proposition in Norstrom (1972), as the sequence of accumulated values of , does not change sign, it follows that has a unique internal rate of return. Which is, in this case, null. Since present values of the interest sequences of both cases, single and multiple , at interest rate , that denotes the financial institution cost of capital, are . With being relative to the same period as the financing rate i. With:
Table 2: Multiple Contracts
| k | $F_k = A'_k$ | $J'_k$ | $p_k$ | $J_k$ | $d_k = J_k - J'_k$ | $\Delta_k$ |
| 1 | 5,529.36 | 55.29 | 5,584.66 | 1,000.00 | 944.71 | 944.71 |
| 2 | 5,474.62 | 110.04 | 5,584.66 | 954.15 | 844.11 | ,788.82 |
| 3 | 15,126.32 | 458.34 | 15,584.66 | 907.85 | 449.51 | ,238.33 |
| 4 | 5,366.75 | 217.91 | 5,584.66 | 761.08 | 543.17 | 2,781.49 |
| 5 | 5,313.61 | 271.05 | 5,584.66 | 712.84 | 441.80 | 3,223.29 |
| 6 | 14,601.45 | 903.21 | 15,584.66 | 644.13 | -239.08 | 2,984.21 |
| 7 | 5,208.91 | 375.75 | 5,584.66 | 514.92 | 139.17 | 3,123.39 |
| 8 | 5,157.34 | 427.32 | 5,584.66 | 464.22 | 36.90 | 3,160.29 |
| 9 | 14,249.67 | 1,334.98 | 15,584.66 | 413.02 | -921.97 | 2,238.33 |
| 10 | 5,055.72 | 528.94 | 5,584.66 | 261.30 | -267.64 | 1,970.69 |
| 11 | 5,005.66 | 579.00 | 5,584.66 | 208.07 | -370.93 | 1,599.76 |
| 12 | 13,830.59 | 1,754.07 | 15,584.66 | 154.30 | -1,599.76 | 0.00 |
| $\Sigma$ | 00,000.00 | 7,015.89 | 107,015.89 | 7,015.89 | 0.00 |
As previously noted, the first point that should be observed is that, although the sum of the parcels of interest are the same in the case of a single contract and in the case of multiple contracts, the timing and the values of their respective payments are not the same.
Considering the period of i and one month, Table 3 shows, for our example, the present values of the interest sequences for several values of the cost of capital, in annual terms, .
Table 3: Present values of and
| $\rho_a$ | $\rho$ | $V_s(\rho)$ | $V_m(\rho)$ | %(difference) |
| 5% | 0.40741% | 6,879.47 | 6,776.37 | 1.52142% |
| 10% | 0.79741% | 6,752.80 | 6,556.52 | 2.99373% |
| 15% | 1.17149% | 6,634.79 | 6,353.91 | 4.42046% |
| 20% | 1.53095% | 6,524.48 | 6,166.52 | 5.80477% |
| 25% | 1.87693% | 6,421.07 | 5,992.62 | 7.14949% |
| 30% | 2.21045% | 6,323.86 | 5,830.75 | 8.45713% |
Therefore, in the case of our simple numerical example, we have , if . Consequently, the financial institution providing the loan should prefer to implement the multiple contracts option.
Although a more general analysis should consider the case where the periodic balloon payments P can assume any value, as long , otherwise p would either be null or negative, we are going to focus attention on the case where P = p. Since this is the case that better contemplates the Brazilian peculiarity of thirteen yearly wages of the employees.
In this case, it follows, from equation (2) (see appendix A for demonstration), that the value of the periodic and balloon payments, p, will be such that:
As a numerical illustration, consider the case where , i=1% per period, n=24 and l=2. Observing that we will have 24 periodic payments equal to p=\$4,363.31, plus the two payments of the same value at epoch 12 and epoch 24. Table 4 presents the evolution of the debt of a single contract of this case and Table 5 the corresponding multiple contracts.
Table 4: Evolution of the debt Single contract – "thirteenth wage"
| Epoch (k) | $J_{k}$ | $A_{k}$ | $p_{k}$ | $S_{k}$ |
| 0 | 100,000.00 | |||
| 1 | 1,000.00 | 3,363.31 | 4,363.31 | 96,636.69 |
| 2 | 966.37 | 3,396.94 | 4,363.31 | 93,239.76 |
| 3 | 932.40 | 3,430.91 | 4,363.31 | 89,808.85 |
| ⋮ | ⋮ | ⋮ | ⋮ | ⋮ |
| 11 | 648.12 | 3,715.18 | 4,363.31 | 61,097.20 |
| 12 | 610.97 | 8,115.64 | 8,726.61 | 52,981.56 |
| 13 | 529.82 | 3,833.49 | 4,363.31 | 49,148.07 |
| ⋮ | ⋮ | ⋮ | ⋮ | ⋮ |
| 22 | 170.67 | 4,192.63 | 4,363.31 | 12,874.77 |
| 23 | 128.75 | 4,234.56 | 4,363.31 | 8,640.21 |
| 24 | 86.40 | 8,640.21 | 8,726.61 | 0.00 |
| Σ | 13,445.95 | 100,000.00 | 113,445.95 |
also has more than one change of sign, the sequence of its accumulated values has no change of sign. Therefore, the sequence of differences has a unique internal rate of return. Consequently, we are assured that for all Table 6 shows the values of and
| k | $F_k = A'_k$ | $J'_k$ | $p_k$ | $J_k$ | $d_k = J_k - J'_k$ | $\Delta_k$ |
| 1 | 4,320.10 | 43.20 | 4,363.31 | 1,000.00 | 956.80 | 956.80 |
| 2 | 4,277.33 | 85.97 | 4,363.31 | 966.37 | 880.39 | 1,837.19 |
| 3 | 4,234.98 | 128.32 | 4,363.31 | 932.40 | 804.07 | 2,641.26 |
| ⋮ | ⋮ | ⋮ | ⋮ | ⋮ | ⋮ | ⋮ |
| 11 | 3,910.93 | 452.37 | 4,363.31 | 648.12 | 195.75 | 6,334.33 |
| 12 | 7,744.42 | 982.19 | 8,726.61 | 610.97 | -371.21 | 5,963.12 |
| 13 | 3,833.87 | 529.43 | 4,363.31 | 529.82 | 0.38 | 5,963.50 |
| ⋮ | ⋮ | ⋮ | ⋮ | ⋮ | ⋮ | ⋮ |
| 22 | 3,505.46 | 857.84 | 4,363.31 | 170.67 | -687.17 | 2,531.23 |
| 23 | 3,470.76 | 892.55 | 4,363.31 | 128.75 | -763.80 | 1,767.43 |
| 24 | 6,872.78 | 1,853.83 | 8,726.61 | 86.40 | -1,767.43 | 0.00 |
| Σ | 100,000.00 | 13,445.95 | 113,445.95 | 13,445.95 | 0.00 | - |
Table 6: Present value of interest sequences. – Constant Installments That is, at least in the case of our simple numerical example, with n equal to 24 periods (24 months and 2 years), the financial institution should choose to implement the multiple contracts option.
| $\rho_a$ | $\rho$ | $V_s(\rho)$ | $V_m(\rho)$ | %(difference) |
| 5% | 0.40741% | 25,111.16 | 24,720.56 | 1.58007% |
| 10% | 0.79741% | 23,553.18 | 22,826.50 | 3.18346% |
| 15% | 1.17149% | 22,180.97 | 21,163.52 | 4.80757% |
| 20% | 1.53095% | 20,965.03 | 19,694.71 | 6.45002% |
| 25% | 1.87693% | 19,881.53 | 18,390.32 | 8.10863% |
| 30% | 2.21045% | 18,911.09 | 17,226.13 | 9.78142% |
4.1. Reduction in the value of the installments
Given that, considering a contract with a term of n years, the effect of the "thirteenth wage" is to imply the value of the monthly payments to be reduced, as compared to the case of no "thirteenth wage", it is interesting to give a numerical illustration of the size of the reduction.
For instance, considering the constant installments methods, if the contract has a term of n = 20 years, with i = 1% per month, with and without the "thirteenth wage", it follows that the value of the monthly payment will be p = $ 1,101.09. While in the case of the “thirteenth wage”, the value of the resulting monthly payment will be p'=$1,020.61. That is, we will have a reduction of 7.31% in the value of the monthly payment.
However, as shown in Table 7, the resulting reduction decreases when the value of the financing interest rate i is increased. Furthermore, for every value of i, the resulting reduction does not change with the value of the term n.
Table 7: Percentual reduction of installments IV. GENERAL ANALYSIS
| 120 months | 240 months | |||||
| Int. Rate | Original | 13Wages | Δ% | Original | 13Wages | Δ% |
| 0.50% | 1,110.21 | 1,026.95 | -7.499% | 716.43 | 662.71 | -7.499% |
| 1.00% | 1,434.71 | 1,329.85 | -7.309% | 1,101.09 | 1,020.61 | -7.309% |
| 1.50% | 1,801.85 | 1,673.53 | -7.122% | 1,543.31 | 1,433.40 | -7.122% |
| 2.00% | 2,204.81 | 2,051.83 | -6.939% | 2,017.41 | 1,877.43 | -6.939% |
| 2.50% | 2,636.18 | 2,458.01 | -6.759% | 2,506.69 | 2,337.27 | -6.759% |
| 3.00% | 3,088.99 | 2,885.66 | -6.582% | 3,002.49 | 2,804.86 | -6.582% |
A comprehensive analysis would have to consider different values of the periodicity m of the balloon payments. However, given that De-Losso et al. (2013), did not address the behavior of what can be defined as the fiscal gain , given by:
We are going to focus on only two cases. The one with no balloon payments and the one with the "thirteenth wage".
5.1. The case of periodic payments only
In Tables 8 to 13, a comparison of single and multiple contracts values of are presented. In terms of the annual cost of capital value , for different values of the monthly interest rate i, for contracts with term n ranging from 5 to 30 years.
Table 8: Fiscal Gain Comparison – monthly interest rate i=0.5% p.m.
| Constant Installments - Single vs. Multiple Contracts | ||||||
| $\rho_a(\%)$ | ||||||
| n(years) | 5% | 10% | 15% | 20% | 25% | 30% |
| 5 | 7.8844 | 15.9577 | 24.1931 | 32.5645 | 41.0469 | 49.6169 |
| 10 | 15.6432 | 32.6397 | 50.8269 | 70.0162 | 90.0068 | 110.5986 |
| 15 | 23.0441 | 49.2608 | 78.1367 | 109.0285 | 141.2650 | 174.2288 |
| 20 | 30.0078 | 65.3012 | 104.6218 | 146.4624 | 189.4352 | 232.4757 |
| 25 | 36.4748 | 80.3036 | 128.9813 | 179.8554 | 230.9162 | 280.9682 |
| 30 | 42.4060 | 93.9206 | 150.3444 | 207.9367 | 264.4861 | 319.0548 |
Table 9: Fiscal Gain Comparison – monthly interest rate i=1.0% p.m.
| Constant Installments - Single vs. Multiple Contracts | ||||||
| $\rho_a(\%)$ | ||||||
| n(years) | 5% | 10% | 15% | 20% | 25% | 30% |
| 5 | 7.4709 | 15.0921 | 22.8383 | 30.6852 | 38.6100 | 46.5914 |
| 10 | 14.0198 | 29.0432 | 44.9101 | 61.4475 | 78.4809 | 95.8444 |
| 15 | 19.5047 | 41.0777 | 64.2314 | 88.4350 | 113.1899 | 138.0765 |
| 20 | 23.9956 | 50.9828 | 79.8946 | 109.6788 | 139.5020 | 168.8095 |
| 25 | 27.6074 | 58.8032 | 91.7529 | 124.9283 | 157.3894 | 188.6977 |
| 30 | 30.4732 | 64.7578 | 100.2201 | 135.1035 | 168.6416 | 200.6545 |
Table 10: Fiscal Gain Comparison – monthly interest rate i=1.5% p.m.
| Constant Installments - Single vs. Multiple Contracts | ||||||
| $\rho_a(\%)$ | ||||||
| n(years) | 5% | 10% | 15% | 20% | 25% | 30% |
| 5 | 7.0804 | 14.2775 | 21.5676 | 28.9286 | 36.3396 | 43.7814 |
| 10 | 12.5912 | 25.9196 | 39.8353 | 54.1847 | 68.8199 | 83.6058 |
| 15 | 16.6379 | 34.6202 | 53.5221 | 72.9240 | 92.4622 | 111.8538 |
| 20 | 19.5387 | 40.7879 | 62.9157 | 85.2034 | 107.1470 | 128.4546 |
| 25 | 21.5953 | 44.9934 | 68.9223 | 92.4864 | 115.2285 | 136.9947 |
| 30 | 23.0520 | 47.7821 | 72.5546 | 96.4879 | 119.3078 | 141.0251 |
Table 11: Fiscal Gain Comparison – monthly interest rate i=2.0% p.m.
| Constant Installments - Single vs. Multiple Contracts | ||||||
| $\rho_a(\%)$ | ||||||
| n(years) | 5% | 10% | 15% | 20% | 25% | 30% |
| 5 | 6.7127 | 13.5130 | 20.3792 | 27.2909 | 34.2293 | 41.1772 |
| 10 | 11.3444 | 23.2246 | 35.5046 | 48.0510 | 60.7398 | 73.4620 |
| 15 | 14.3369 | 29.5463 | 45.2718 | 61.1867 | 77.0260 | 92.5980 |
| 20 | 16.2431 | 33.4752 | 51.0616 | 68.5062 | 85.4967 | 101.8767 |
| 25 | 17.4684 | 35.8643 | 54.2986 | 72.2220 | 89.4012 | 105.7919 |
| 30 | 18.2744 | 37.3076 | 56.0386 | 73.9866 | 91.0552 | 107.2993 |
Table 12: Fiscal Gain Comparison – monthly interest rate i=2.5% p.m.
| Constant Installments - Single vs. Multiple Contracts | ||||||
| $\rho_a(\%)$ | ||||||
| n(years) | 5% | 10% | 15% | 20% | 25% | 30% |
| 5 | 6.3673 | 12.7974 | 19.2702 | 25.7672 | 32.2715 | 38.7677 |
| 10 | 10.2616 | 20.9078 | 31.8173 | 42.8755 | 53.9793 | 65.0411 |
| 15 | 12.4920 | 25.5477 | 38.8727 | 52.2124 | 65.3724 | 78.2212 |
| 20 | 13.7799 | 28.1330 | 42.5733 | 56.7506 | 70.4649 | 83.6319 |
| 25 | 14.5535 | 29.5831 | 44.4504 | 58.8007 | 72.5100 | 85.5775 |
| 30 | 15.0423 | 30.4135 | 45.3891 | 59.6855 | 73.2758 | 86.2199 |
Table 13: Fiscal Gain Comparison – monthly interest rate i=3.0% p.m.
| Constant Installments - Single vs. Multiple Contracts | ||||||
| $\rho_a(\%)$ | ||||||
| n(years) | 5% | 10% | 15% | 20% | 25% | 30% |
| 5 | 6.0437 | 12.1289 | 18.2372 | 24.3519 | 30.4578 | 36.5415 |
| 10 | 9.3237 | 18.9184 | 28.6775 | 38.5028 | 48.3090 | 58.0256 |
| 15 | 11.0061 | 22.3717 | 33.8545 | 45.2545 | 56.4275 | 67.2821 |
| 20 | 11.9057 | 24.1377 | 36.3187 | 48.1948 | 59.6342 | 70.5915 |
| 25 | 12.4241 | 25.0787 | 37.4909 | 49.4210 | 60.8012 | 71.6479 |
| 30 | 12.7459 | 25.6036 | 38.0551 | 49.9222 | 61.2064 | 71.9629 |
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As shown, in all cases the fiscal gain is substantial. Which implies that the financial institution providing the loan should always choose the option of implementing multiple contracts.
5.2. The case of the "thirteenth wage"
Analogously, Tables 14 to 19 present the value of the fiscal gain , in terms of the annual value for different values of the monthly interest rate i, for contracts with length n of 5 to 30 years.
Additionally, fixing the financing interest rate i at 1% per month, Figures 3 and 4 depict the behavior of the fiscal gain, respectively for the cases where the opportunity cost varies from 5% to 30% per year, and when the length of the contract varies from 5 to 30 years, for the case of thirteen wages.
Table 14: Fiscal Gain Comparison 13 Wages – monthly interest rate i=0.5% p.m.
| Constant Installments - Single vs. Multiple Contracts – 13 Wages | ||||||
| $\rho_a(\%)$ | ||||||
| n(years) | 5% | 10% | 15% | 20% | 25% | 30% |
| 5 | 7.9499 | 16.0955 | 24.4096 | 32.8657 | 41.4385 | 50.1043 |
| 10 | 15.7020 | 32.7705 | 51.0423 | 70.3276 | 90.4246 | 111.1317 |
| 15 | 23.0986 | 49.3869 | 78.3498 | 109.3411 | 141.6869 | 174.7680 |
| 20 | 30.0583 | 65.4209 | 104.8252 | 146.7593 | 189.8330 | 232.9811 |
| 25 | 36.5212 | 80.4147 | 129.1682 | 180.1247 | 231.2740 | 281.4229 |
| 30 | 42.4484 | 94.0214 | 150.5109 | 208.1736 | 264.8009 | 319.4594 |
Table 15: Fiscal Gain Comparison 13 Wages – monthly interest rate i=1.0% p.m.
| Constant Installments - Single vs. Multiple Contracts – 13Wages | ||||||
| $\rho_a(\%)$ | ||||||
| n(years) | 5% | 10% | 15% | 20% | 25% | 30% |
| 5 | 7.5300 | 15.2162 | 23.0327 | 30.9551 | 38.9602 | 47.0264 |
| 10 | 14.0668 | 29.1469 | 45.0793 | 61.6900 | 78.8037 | 96.2536 |
| 15 | 19.5431 | 41.1647 | 64.3755 | 88.6429 | 113.4669 | 138.4274 |
| 20 | 24.0268 | 51.0542 | 80.0123 | 109.8471 | 139.7251 | 169.0926 |
| 25 | 27.6326 | 58.8604 | 91.8460 | 125.0606 | 157.5658 | 188.9256 |
| 30 | 30.4934 | 64.8031 | 100.2929 | 135.2076 | 168.7842 | 200.8451 |
Table 16: Fiscal Gain Comparison 13 Wages – monthly interest rate i=1.5% p.m.
| Constant Installments - Single vs. Multiple Contracts – 13Wages | ||||||
| $\rho_a(\%)$ | ||||||
| n(years) | 5% | 10% | 15% | 20% | 25% | 30% |
| 5 | 7.1337 | 14.3891 | 21.7423 | 29.1706 | 36.6531 | 44.1701 |
| 10 | 12.6290 | 26.0020 | 39.9688 | 54.3750 | 69.0718 | 83.9237 |
| 15 | 16.6652 | 34.6812 | 53.6218 | 73.0666 | 92.6515 | 112.0934 |
| 20 | 19.5585 | 40.8324 | 62.9884 | 85.3072 | 107.2857 | 128.6328 |
| 25 | 21.6098 | 45.0260 | 68.9755 | 92.5634 | 115.3343 | 137.1359 |
| 30 | 23.0629 | 47.8065 | 72.5949 | 96.5486 | 119.3953 | 141.1473 |
Table 17: Fiscal Gain Comparison 13 Wages – monthly interest rate i=2.0% p.m.
| Constant Installments - Single vs. Multiple Contracts – 13Wages | ||||||
| $\rho_a(\%)$ | ||||||
| n(years) | 5% | 10% | 15% | 20% | 25% | 30% |
| 5 | 6.7608 | 13.6135 | 20.5362 | 27.5082 | 34.5103 | 41.5252 |
| 10 | 11.3747 | 23.2906 | 35.6110 | 48.2020 | 60.9392 | 73.7132 |
| 15 | 14.3567 | 29.5902 | 45.3434 | 61.2890 | 77.1622 | 92.7714 |
| 20 | 16.2563 | 33.5050 | 51.1106 | 68.5772 | 85.5934 | 102.0036 |
| 25 | 17.4777 | 35.8855 | 54.3342 | 72.2754 | 89.4773 | 105.8967 |
| 30 | 18.2813 | 37.3235 | 56.0666 | 74.0310 | 91.1220 | 107.3949 |
Table 18: Fiscal Gain Comparison 13 Wages – monthly interest rate i=2.5% p.m.
| Constant Installments - Single vs. Multiple Contracts – 13Wages | ||||||
| $\rho_a(\%)$ | ||||||
| n(years) | 5% | 10% | 15% | 20% | 25% | 30% |
| 5 | 6.4107 | 12.8880 | 19.4115 | 25.9625 | 32.5239 | 39.0801 |
| 10 | 10.2863 | 20.9611 | 31.9032 | 42.9972 | 54.1399 | 65.2436 |
| 15 | 12.5068 | 25.5806 | 38.9265 | 52.2897 | 65.4762 | 78.3547 |
| 20 | 13.7894 | 28.1546 | 42.6095 | 56.8043 | 70.5398 | 83.7323 |
| 25 | 14.5601 | 29.5987 | 44.4775 | 58.8431 | 72.5723 | 85.6649 |
| 30 | 15.0473 | 30.4257 | 45.4117 | 59.7228 | 73.3331 | 86.3026 |
Table 19: Fiscal Gain Comparison 13 Wages – monthly interest rate i=3.0% p.m.
| Constant Installments - Single vs. Multiple Contracts – 13Wages | ||||||
| $\rho_a(\%)$ | ||||||
| n(years) | 5% | 10% | 15% | 20% | 25% | 30% |
| 5 | 6.0829 | 12.2107 | 18.3647 | 24.5279 | 30.6851 | 36.8226 |
| 10 | 9.3439 | 18.9622 | 28.7480 | 38.6028 | 48.4412 | 58.1926 |
| 15 | 11.0175 | 22.3974 | 33.8968 | 45.3161 | 56.5111 | 67.3909 |
| 20 | 11.9130 | 24.1546 | 36.3477 | 48.2389 | 59.6969 | 70.6771 |
| 25 | 12.4293 | 25.0912 | 37.5136 | 49.4576 | 60.8559 | 71.7255 |
| 30 | 12.7499 | 25.6139 | 38.0750 | 49.9557 | 61.2583 | 72.0381 |
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As shown, in all cases fiscal gain is very substantial. Therefore, given that implementing the policy of considering the "thirteenth wage" is beneficial to the borrower, the financial institution providing the loan, should also prefer to adopt the option of substituting a single contract by multiple contracts.
V. CONCLUSIONS
As shown in the other cases previously analyzed, cf. De-Losso et al. (2013), for the case of constant payments, de Faro (2021), for the case of periodic payments only, de Faro (2022), for the case of the constant amortization, de Faro and Lachtermacher (2023b), for the case of the an alternative version of the SACRE, and de Faro and Lachtermacher (2024), for the case of the German system of amortization, it always better for the financial institution providing the loan to implement the policy of multiple contracts.
Appendix A
since
Conflict of Interest
The authors declare no conflict of interest.
Ethical Approval
Not applicable
Data Availability
The datasets used in this study are openly available at [repository link] and the source code is available on GitHub at [GitHub link].
Funding
This work did not receive any external funding.
References
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