MyWikiBiz, Author Your Legacy — Sunday November 16, 2025
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, 20:30, 16 November 2012
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| − | <pre> | + | If <math>L\!</math> is tubular at <math>X,\!</math> then <math>L\!</math> is called a ''partial function'' or a ''prefunction'' from <math>X\!</math> to <math>Y,\!</math> indicated by writing <math>L : X \rightharpoonup Y.\!</math> We have the following definitions and notations. |
| − | If R is tubular at S, then R is called a "partial function" or "prefunction" from S to T, often indicated by writing R = p : S ~> T.
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| − | R = p : S ~> T iff R is tubular at S.
| + | {| align="center" cellspacing="8" width="90%" |
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| | + | <math>\begin{array}{lll} |
| | + | L ~\text{is a prefunction}~ L : X \rightharpoonup Y |
| | + | & \iff & |
| | + | L ~\text{is tubular at}~ X. |
| | + | \\[6pt] |
| | + | L ~\text{is a prefunction}~ L : X \leftharpoonup Y |
| | + | & \iff & |
| | + | L ~\text{is tubular at}~ Y. |
| | + | \end{array}</math> |
| | + | |} |
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| | + | <pre> |
| | If R is a prefunction p : S ~> T that happens to be total at S, then R is called a "function" from S to T, indicated by writing R = f : S > T. | | If R is a prefunction p : S ~> T that happens to be total at S, then R is called a "function" from S to T, indicated by writing R = f : S > T. |
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