+ <td class="snns top green">mr2</td>
+ <td class="snnn top green">mr2_at ( @⦃?,?⦄ ≡ ? )</td>
+ <td class="snnn top green">mr2_plus ( ? + ? )</td>
+ <td class="snnn top green">mr2_minus ( ? ▭ ? ≡ ? )</td>
+ <td class="snnn top green">
+ <br />
+ </td>
+ <td class="ssnn top green">
+ <br />
+ </td>
+ </tr>
+ <tr>
+ <td class="snns top capitalize italic grass">natural numbers with infinity</td>
+ <td class="snns top italic grass" />
+ <td class="snns top grass">ynat ( ∞ )</td>
+ <td class="snnn top grass">ynat_pred ( ⫰? )</td>
+ <td class="snnn top grass">ynat_succ ( ⫯? )</td>
+ <td class="snnn top grass">ynat_le ( ? ≤ ? )</td>
+ <td class="snnn top grass">ynat_lt ( ? < ? )</td>
+ <td class="ssnn top grass">ynat_plus ( ? + ? )</td>