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| <p><math>\operatorname{Conc}^k_j s_j \ = \ \operatorname{Prec}(\operatorname{Conc}^{k-1}_j s_j, s_k).</math></p></li> | | <p><math>\operatorname{Conc}^k_j s_j \ = \ \operatorname{Prec}(\operatorname{Conc}^{k-1}_j s_j, s_k).</math></p></li> |
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− | </ol></ol></ol> | + | </ol></ol> |
| + | |
| + | <li> |
| + | <p>The conception of the <math>k\!</math>-place surcatenation operation can be extended to include its natural "prequel":</p> |
| + | |
| + | <p><math>\operatorname{Surc}^0 \ = \ ^{\backprime\backprime} \, \operatorname{()} \, ^{\prime\prime}.</math></p> |
| + | |
| + | <p>Finally, the construction of the <math>k\!</math>-place surcatenation can be broken into stages by means of the following conceptions:</p> |
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− | <pre> | + | <ol style="list-style-type:lower-alpha"> |
− | 2. The conception of the k-place surcatenation operation
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− | can be extended to include its natural "prequel":
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− | Surc^0 = "-()-".
| + | <li> |
| + | <p>A ''subclause'' in <math>\mathfrak{A}^*</math> is a string that ends with a <math>^{\backprime\backprime} \, \operatorname{)} \, ^{\prime\prime}.</math></p></li> |
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− | Finally, the construction of the k-place surcatenation can be
| + | <li> |
− | broken into stages by means of the following conceptions:
| + | <p>The ''subcatenation'' <math>\operatorname{Subc} (s_1, s_2)</math> of a subclause <math>s_1\!</math> by a string <math>s_2\!</math> is the string that is defined as follows:</p> |
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− | a. A "subclause" in !A!* is a string that ends with a ")-".
| + | <p><math>\operatorname{Subc} (s_1, s_2) \ = \ s_1 \, \cdot \, ^{\backprime\backprime} \, \operatorname{)} \, ^{\prime\prime} \, )^{-1} \, \cdot \, ^{\backprime\backprime} \, \operatorname{,} \, ^{\prime\prime} \, \cdot \, s_2 \, \cdot \, ^{\backprime\backprime} \, \operatorname{)} \, ^{\prime\prime}.</math></p> |
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− | b. The "subcatenation" Subc(z_1, z_2)
| + | <li> |
− | of a subclause z_1 by a string z_2 is
| + | <p>The ''surcatenation'' of the <math>k\!</math> strings <math>s_1, \ldots, s_k\!</math> can now be defined as an iterated subcatenation over the sequence of <math>k + 1\!</math> strings that starts with the string <math>s_0 \ = \ \operatorname{Surc}^0 \ = \ ^{\backprime\backprime} \, \operatorname{()} \, ^{\prime\prime}</math> and then continues on through the other <math>k\!</math> strings:</p></li> |
− | the string that is defined as follows:
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− | Subc(z_1, z_2) = z_1 · ")-"^(-1) · "," · z_2 · ")-".
| + | <ol style="list-style-type:lower-roman"> |
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− | c. The "surcatenation" of the k strings z_1, ..., z_k can now be
| + | <li> |
− | defined as an iterated subcatenation over the sequence of k+1
| + | <p><math>\operatorname{Surc}^0_j s_j \ = \ \operatorname{Surc}^0 \ = \ ^{\backprime\backprime} \, \operatorname{()} \, ^{\prime\prime}.</math></p></li> |
− | strings that starts with the string z_0 = Surc^0 = "-()-" and
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− | then continues on through the other k strings:
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− | i. Surc^0_j z_j = Surc^0 = "-()-".
| + | <li> |
| + | <p>For <math>k > 0,\!</math></p> |
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− | ii. For k > 0,
| + | <p><math>\operatorname{Surc}^k_j s_j \ = \ \operatorname{Subc}(\operatorname{Surc}^{k-1}_j s_j, s_k).</math></p></li> |
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− | Surc^k_j z_j = Subc(Surc^(k-1)_j z_j, z_k).
| + | </ol></ol></ol> |
| | | |
| + | <pre> |
| Notice that the expressions Conc^0_j z_j and Surc^0_j z_j | | Notice that the expressions Conc^0_j z_j and Surc^0_j z_j |
| are defined in such a way that the respective operators | | are defined in such a way that the respective operators |