We have already looked at 2-adic relations that separately exemplify each of these regularities. We also introduced a few bits of additional terminology and special-purpose notations for working with tubular relations:
+
We have already looked at 2-adic relations that separately exemplify each of these regularities. We also introduced a few bits of additional terminology and special-purpose notations for working with tubular relations.
{| align="center" cellspacing="8" width="90%"
{| align="center" cellspacing="8" width="90%"
|
|
<math>\begin{array}{lll}
<math>\begin{array}{lll}
−
L ~\text{is a pre-function}~ L : X \rightharpoonup Y
+
L ~\text{is a prefunction}~ L : X \rightharpoonup Y
& \iff &
& \iff &
L ~\text{is tubular at}~ X.
L ~\text{is tubular at}~ X.
\\[6pt]
\\[6pt]
−
L ~\text{is a pre-function}~ L : X \leftharpoonup Y
+
L ~\text{is a prefunction}~ L : X \leftharpoonup Y