MyWikiBiz, Author Your Legacy — Tuesday November 18, 2025
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, 19:30, 3 July 2008
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| | The briefest expression for logical truth is the empty word, usually denoted by <math>\varepsilon\!</math> or <math>\lambda\!</math> in formal languages, where it forms the identity element for concatenation. To make it visible in this text, I denote it by the equivalent expression "<math>((~))\!</math>", or, especially if operating in an algebraic context, by a simple "<math>1\!</math>". Also when working in an algebraic mode, I use the plus sign "<math>+\!</math>" for exclusive disjunction. Thus, we may express the following paraphrases of algebraic forms: | | The briefest expression for logical truth is the empty word, usually denoted by <math>\varepsilon\!</math> or <math>\lambda\!</math> in formal languages, where it forms the identity element for concatenation. To make it visible in this text, I denote it by the equivalent expression "<math>((~))\!</math>", or, especially if operating in an algebraic context, by a simple "<math>1\!</math>". Also when working in an algebraic mode, I use the plus sign "<math>+\!</math>" for exclusive disjunction. Thus, we may express the following paraphrases of algebraic forms: |
| | | | |
| − | :{| cellpadding="4"
| + | <center> |
| − | | ''A'' + ''B''
| + | <p><math>\begin{matrix} |
| − | | =
| + | x + y & = & (x, y) |
| − | | (''A'', ''B'')
| + | \end{matrix}</math></p> |
| − | |-
| |
| − | | ''A'' + ''B'' + ''C''
| |
| − | | =
| |
| − | | ((''A'', ''B''), ''C'')
| |
| − | | =
| |
| − | | (''A'', (''B'', ''C''))
| |
| − | |}
| |
| | | | |
| − | One should be careful to observe that these last two expressions are not equivalent to the form (''A'', ''B'', ''C'').
| + | <p><math>\begin{matrix} |
| | + | x + y + z & = & ((x, y), z) & = & (x, (y, z)) |
| | + | \end{matrix}</math></p> |
| | + | </center> |
| | + | |
| | + | It is important to note that the last expressions are not equivalent to the triple bracket expression <math>(x, y, z).\!</math> |
| | | | |
| | <font face="courier new"> | | <font face="courier new"> |