components

5reg

components

The components of a knot/link diagram

Content Model
    components ::= (#PCDATA)
Attributes
Name | Type
`size` | `NUMBER` (required)

## Description

A &xml-components; element encodes a starting point for each link component in a knot/link diagram. Recall that, in ®ina;, all knot/link diagrams are oriented.

The total number of components must be specified by the `size` attribute. The individual components are numbered 0, 1, 2, and so on.

The character data of this &xml; element should be a whitespace-separated list of tokens, each representing a starting point for traversing an individual component of the link diagram. There should be `size` tokens in total, representing starting points for components 0, 1, 2, ... in order.

If a component has no crossings (i.e., it is a zero-crossing unknot component), then the corresponding token should be the six-character literal string `(null)`. Otherwise the token should be in one of the two forms `^``k`, representing the upper strand of crossing number `k`, or `_``k`, representing the lower strand of crossing number `k`. Here the symbols `^` and `_` are literal characters, whereas `k` should be replaced by a crossing number. Recall that ®ina; numbers crossings beginning at 0.

### Parents

The following elements contain `components`:

- &xml-link;

.

### Children

Element `components` has no children.

## Attributes

`size`

- The total number of components in the link diagram.

## Example

The following &xml; snippet represents the Whitehead link.

    <crossings size="5">
    - - + + -
    </crossings>
    <connections>
    _1 ^1
    _2 ^4
    _4 ^3
    _0 ^2
    _3 ^0
    </connections>
    <components size="2">
    ^0 _0
    </components>