Line 555: |
Line 555: |
| The intention of this operator is that we evaluate the proposition <math>q\!</math> on each model of the proposition <math>p\!</math> and combine the results according to the method indicated by the connective parameter <math>r.\!</math> In principle, the index <math>r\!</math> might specify any connective on as many as <math>2^k\!</math> arguments, but usually we have in mind a much simpler form of combination, most often either collective products or collective sums. By convention, each of the accessory indices <math>p, r\!</math> is assigned a default value that is understood to be in force when the corresponding argument place is left blank, specifically, the constant proposition <math>1 : \mathbb{B}^k \to \mathbb{B}</math> for the lower index <math>p,\!</math> and the continued conjunction or continued product operation <math>\textstyle\prod</math> for the upper index <math>r.\!</math> Taking the upper default value gives license to the following readings: | | The intention of this operator is that we evaluate the proposition <math>q\!</math> on each model of the proposition <math>p\!</math> and combine the results according to the method indicated by the connective parameter <math>r.\!</math> In principle, the index <math>r\!</math> might specify any connective on as many as <math>2^k\!</math> arguments, but usually we have in mind a much simpler form of combination, most often either collective products or collective sums. By convention, each of the accessory indices <math>p, r\!</math> is assigned a default value that is understood to be in force when the corresponding argument place is left blank, specifically, the constant proposition <math>1 : \mathbb{B}^k \to \mathbb{B}</math> for the lower index <math>p,\!</math> and the continued conjunction or continued product operation <math>\textstyle\prod</math> for the upper index <math>r.\!</math> Taking the upper default value gives license to the following readings: |
| | | |
− | {| cellpadding="4" | + | {| align="center" cellpadding="8" style="text-align:center" |
− | | align="right" width="36" | 1.
| + | | <math>\Upsilon_p (q) = \Upsilon (p, q) = \Upsilon (p, q, \textstyle\prod).</math> |
− | | <math>\Upsilon_p q = \Upsilon (p, q) = \Upsilon (p, q, \textstyle\prod).</math> | |
| |- | | |- |
− | | align="right" width="36" | 2.
| |
| | <math>\Upsilon_p = \Upsilon (p, \underline{~~}, \textstyle\prod) : (\mathbb{B}^k \to \mathbb{B}) \to \mathbb{B}.</math> | | | <math>\Upsilon_p = \Upsilon (p, \underline{~~}, \textstyle\prod) : (\mathbb{B}^k \to \mathbb{B}) \to \mathbb{B}.</math> |
− | |}<br> | + | |} |
| | | |
− | This means that <math>\Upsilon_p q = 1\!</math> if and only if <math>q\!</math> holds for all models of <math>p.\!</math> In propositional terms, this is tantamount to the assertion that <math>p \Rightarrow q,</math> or that <math>(\!| p (\!| q |\!) |\!) = 1.</math> | + | This means that <math>\Upsilon_p (q) = 1\!</math> if and only if <math>q\!</math> holds for all models of <math>p.\!</math> In propositional terms, this is tantamount to the assertion that <math>p \Rightarrow q,</math> or that <math>\underline{(p (q))} = \underline{1}.</math> |
| | | |
| Throwing in the lower default value permits the following abbreviations: | | Throwing in the lower default value permits the following abbreviations: |
| | | |
− | {| cellpadding="4" | + | {| align="center" cellpadding="8" style="text-align:center" |
− | | align="right" width="36" | 3.
| + | | <math>\Upsilon q = \Upsilon (q) = \Upsilon_1 (q) = \Upsilon (1, q, \textstyle\prod).</math> |
− | | <math>\Upsilon q = \Upsilon (q) = \Upsilon_1 q = \Upsilon (1, q, \textstyle\prod).</math> | |
| |- | | |- |
− | | align="right" width="36" | 4.
| |
| | <math>\Upsilon = \Upsilon (1, \underline{~~}, \textstyle\prod)) : (\mathbb{B}^k\ \to \mathbb{B}) \to \mathbb{B}.</math> | | | <math>\Upsilon = \Upsilon (1, \underline{~~}, \textstyle\prod)) : (\mathbb{B}^k\ \to \mathbb{B}) \to \mathbb{B}.</math> |
− | |}<br> | + | |} |
| | | |
| This means that <math>\Upsilon q = 1\!</math> if and only if <math>q\!</math> holds for the whole universe of discourse in question, that is, if and only <math>q\!</math> is the constantly true proposition <math>1 : \mathbb{B}^k \to \mathbb{B}.</math> The ambiguities of this usage are not a problem so long as we distinguish the context of definition from the context of application and restrict all shorthand notations to the latter. | | This means that <math>\Upsilon q = 1\!</math> if and only if <math>q\!</math> holds for the whole universe of discourse in question, that is, if and only <math>q\!</math> is the constantly true proposition <math>1 : \mathbb{B}^k \to \mathbb{B}.</math> The ambiguities of this usage are not a problem so long as we distinguish the context of definition from the context of application and restrict all shorthand notations to the latter. |