An mo element represents an operator or anything that should be rendered as an operator. In MathML the list of things that should "render as an operator" includes a number of notations that are not mathematical operators in the ordinary sense. Besides ordinary operators with infix, prefix, or postfix forms, these include fence characters such as braces, parentheses, and "absolute value" bars; separators such as comma and semicolon; and mathematical accents such as a bar or tilde over a symbol. MathML Fundamentals
<math mathsize="28">
<mspace linebreak="newline" indentalign="center"></mspace>
<mtext style="border:1px;" mathsize="40">Operators - arrows</mtext>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>221A</mtext>
<mrow>
<mo style="border:1px">√</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >√</mo>
<mo style="border:1px" minsize="2" maxsize="2">√</mo>
<mo style="border:1px" minsize="5">√</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>2044</mtext>
<mrow>
<mo style="border:1px">⁄</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⁄</mo>
<mo style="border:1px" minsize="2" maxsize="2">⁄</mo>
<mo style="border:1px" minsize="5">⁄</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>2191</mtext>
<mrow>
<mo style="border:1px">↑</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↑</mo>
<mo style="border:1px" minsize="2" maxsize="2">↑</mo>
<mo style="border:1px" minsize="5">↑</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>2193</mtext>
<mrow>
<mo style="border:1px">↓</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↓</mo>
<mo style="border:1px" minsize="2" maxsize="2">↓</mo>
<mo style="border:1px" minsize="5">↓</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>2195</mtext>
<mrow>
<mo style="border:1px">↕</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↕</mo>
<mo style="border:1px" minsize="2" maxsize="2">↕</mo>
<mo style="border:1px" minsize="5">↕</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>219F</mtext>
<mrow>
<mo style="border:1px">↟</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↟</mo>
<mo style="border:1px" minsize="2" maxsize="2">↟</mo>
<mo style="border:1px" minsize="5">↟</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21A1</mtext>
<mrow>
<mo style="border:1px">↡</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↡</mo>
<mo style="border:1px" minsize="2" maxsize="2">↡</mo>
<mo style="border:1px" minsize="5">↡</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>2190</mtext>
<mrow>
<mo style="border:1px">←</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >←</mo>
<mo style="border:1px" minsize="2" maxsize="2">←</mo>
<mo style="border:1px" minsize="5">←</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>2192</mtext>
<mrow>
<mo style="border:1px">→</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >→</mo>
<mo style="border:1px" minsize="2" maxsize="2">→</mo>
<mo style="border:1px" minsize="5">→</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>2194</mtext>
<mrow>
<mo style="border:1px">↔</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↔</mo>
<mo style="border:1px" minsize="2" maxsize="2">↔</mo>
<mo style="border:1px" minsize="5">↔</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>219E</mtext>
<mrow>
<mo style="border:1px">↞</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↞</mo>
<mo style="border:1px" minsize="2" maxsize="2">↞</mo>
<mo style="border:1px" minsize="5">↞</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21A0</mtext>
<mrow>
<mo style="border:1px">↠</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↠</mo>
<mo style="border:1px" minsize="2" maxsize="2">↠</mo>
<mo style="border:1px" minsize="5">↠</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21A2</mtext>
<mrow>
<mo style="border:1px">↢</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↢</mo>
<mo style="border:1px" minsize="2" maxsize="2">↢</mo>
<mo style="border:1px" minsize="5">↢</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21A3</mtext>
<mrow>
<mo style="border:1px">↣</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↣</mo>
<mo style="border:1px" minsize="2" maxsize="2">↣</mo>
<mo style="border:1px" minsize="5">↣</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21A4</mtext>
<mrow>
<mo style="border:1px">↤</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↤</mo>
<mo style="border:1px" minsize="2" maxsize="2">↤</mo>
<mo style="border:1px" minsize="5">↤</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21A6</mtext>
<mrow>
<mo style="border:1px">↦</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↦</mo>
<mo style="border:1px" minsize="2" maxsize="2">↦</mo>
<mo style="border:1px" minsize="5">↦</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21A9</mtext>
<mrow>
<mo style="border:1px">↩</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↩</mo>
<mo style="border:1px" minsize="2" maxsize="2">↩</mo>
<mo style="border:1px" minsize="5">↩</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21AA</mtext>
<mrow>
<mo style="border:1px">↪</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↪</mo>
<mo style="border:1px" minsize="2" maxsize="2">↪</mo>
<mo style="border:1px" minsize="5">↪</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21AB</mtext>
<mrow>
<mo style="border:1px">↫</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↫</mo>
<mo style="border:1px" minsize="2" maxsize="2">↫</mo>
<mo style="border:1px" minsize="5">↫</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21AC</mtext>
<mrow>
<mo style="border:1px">↬</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↬</mo>
<mo style="border:1px" minsize="2" maxsize="2">↬</mo>
<mo style="border:1px" minsize="5">↬</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21A5</mtext>
<mrow>
<mo style="border:1px">↥</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↥</mo>
<mo style="border:1px" minsize="2" maxsize="2">↥</mo>
<mo style="border:1px" minsize="5">↥</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21A7</mtext>
<mrow>
<mo style="border:1px">↧</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↧</mo>
<mo style="border:1px" minsize="2" maxsize="2">↧</mo>
<mo style="border:1px" minsize="5">↧</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21A8</mtext>
<mrow>
<mo style="border:1px">↨</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↨</mo>
<mo style="border:1px" minsize="2" maxsize="2">↨</mo>
<mo style="border:1px" minsize="5">↨</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21B0</mtext>
<mrow>
<mo style="border:1px">↰</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↰</mo>
<mo style="border:1px" minsize="2" maxsize="2">↰</mo>
<mo style="border:1px" minsize="5">↰</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21B1</mtext>
<mrow>
<mo style="border:1px">↱</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↱</mo>
<mo style="border:1px" minsize="2" maxsize="2">↱</mo>
<mo style="border:1px" minsize="5">↱</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21B2</mtext>
<mrow>
<mo style="border:1px">↲</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↲</mo>
<mo style="border:1px" minsize="2" maxsize="2">↲</mo>
<mo style="border:1px" minsize="5">↲</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21B3</mtext>
<mrow>
<mo style="border:1px">↳</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↳</mo>
<mo style="border:1px" minsize="2" maxsize="2">↳</mo>
<mo style="border:1px" minsize="5">↳</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21B4</mtext>
<mrow>
<mo style="border:1px">↴</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↴</mo>
<mo style="border:1px" minsize="2" maxsize="2">↴</mo>
<mo style="border:1px" minsize="5">↴</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21B5</mtext>
<mrow>
<mo style="border:1px">↵</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↵</mo>
<mo style="border:1px" minsize="2" maxsize="2">↵</mo>
<mo style="border:1px" minsize="5">↵</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21B9</mtext>
<mrow>
<mo style="border:1px">↹</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↹</mo>
<mo style="border:1px" minsize="2" maxsize="2">↹</mo>
<mo style="border:1px" minsize="5">↹</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21C4</mtext>
<mrow>
<mo style="border:1px">⇄</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇄</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇄</mo>
<mo style="border:1px" minsize="5">⇄</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21BC</mtext>
<mrow>
<mo style="border:1px">↼</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↼</mo>
<mo style="border:1px" minsize="2" maxsize="2">↼</mo>
<mo style="border:1px" minsize="5">↼</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21BD</mtext>
<mrow>
<mo style="border:1px">↽</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↽</mo>
<mo style="border:1px" minsize="2" maxsize="2">↽</mo>
<mo style="border:1px" minsize="5">↽</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21BE</mtext>
<mrow>
<mo style="border:1px">↾</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↾</mo>
<mo style="border:1px" minsize="2" maxsize="2">↾</mo>
<mo style="border:1px" minsize="5">↾</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21BF</mtext>
<mrow>
<mo style="border:1px">↿</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >↿</mo>
<mo style="border:1px" minsize="2" maxsize="2">↿</mo>
<mo style="border:1px" minsize="5">↿</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21C2</mtext>
<mrow>
<mo style="border:1px">⇂</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇂</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇂</mo>
<mo style="border:1px" minsize="5">⇂</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21C3</mtext>
<mrow>
<mo style="border:1px">⇃</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇃</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇃</mo>
<mo style="border:1px" minsize="5">⇃</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21C5</mtext>
<mrow>
<mo style="border:1px">⇅</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇅</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇅</mo>
<mo style="border:1px" minsize="5">⇅</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21C8</mtext>
<mrow>
<mo style="border:1px">⇈</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇈</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇈</mo>
<mo style="border:1px" minsize="5">⇈</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21CA</mtext>
<mrow>
<mo style="border:1px">⇊</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇊</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇊</mo>
<mo style="border:1px" minsize="5">⇊</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21D1</mtext>
<mrow>
<mo style="border:1px">⇑</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇑</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇑</mo>
<mo style="border:1px" minsize="5">⇑</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21C0</mtext>
<mrow>
<mo style="border:1px">⇀</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇀</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇀</mo>
<mo style="border:1px" minsize="5">⇀</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21C1</mtext>
<mrow>
<mo style="border:1px">⇁</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇁</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇁</mo>
<mo style="border:1px" minsize="5">⇁</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21C6</mtext>
<mrow>
<mo style="border:1px">⇆</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇆</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇆</mo>
<mo style="border:1px" minsize="5">⇆</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21C7</mtext>
<mrow>
<mo style="border:1px">⇇</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇇</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇇</mo>
<mo style="border:1px" minsize="5">⇇</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21C9</mtext>
<mrow>
<mo style="border:1px">⇉</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇉</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇉</mo>
<mo style="border:1px" minsize="5">⇉</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21CB</mtext>
<mrow>
<mo style="border:1px">⇋</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇋</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇋</mo>
<mo style="border:1px" minsize="5">⇋</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21CC</mtext>
<mrow>
<mo style="border:1px">⇌</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇌</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇌</mo>
<mo style="border:1px" minsize="5">⇌</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21D0</mtext>
<mrow>
<mo style="border:1px">⇐</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇐</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇐</mo>
<mo style="border:1px" minsize="5">⇐</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21D2</mtext>
<mrow>
<mo style="border:1px">⇒</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇒</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇒</mo>
<mo style="border:1px" minsize="5">⇒</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21D4</mtext>
<mrow>
<mo style="border:1px">⇔</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇔</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇔</mo>
<mo style="border:1px" minsize="5">⇔</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21DA</mtext>
<mrow>
<mo style="border:1px">⇚</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇚</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇚</mo>
<mo style="border:1px" minsize="5">⇚</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21D3</mtext>
<mrow>
<mo style="border:1px">⇓</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇓</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇓</mo>
<mo style="border:1px" minsize="5">⇓</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21D5</mtext>
<mrow>
<mo style="border:1px">⇕</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇕</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇕</mo>
<mo style="border:1px" minsize="5">⇕</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21E7</mtext>
<mrow>
<mo style="border:1px">⇧</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇧</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇧</mo>
<mo style="border:1px" minsize="5">⇧</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21E9</mtext>
<mrow>
<mo style="border:1px">⇩</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇩</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇩</mo>
<mo style="border:1px" minsize="5">⇩</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21EA</mtext>
<mrow>
<mo style="border:1px">⇪</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇪</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇪</mo>
<mo style="border:1px" minsize="5">⇪</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21DB</mtext>
<mrow>
<mo style="border:1px">⇛</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇛</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇛</mo>
<mo style="border:1px" minsize="5">⇛</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21E4</mtext>
<mrow>
<mo style="border:1px">⇤</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇤</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇤</mo>
<mo style="border:1px" minsize="5">⇤</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21E5</mtext>
<mrow>
<mo style="border:1px">⇥</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇥</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇥</mo>
<mo style="border:1px" minsize="5">⇥</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21E6</mtext>
<mrow>
<mo style="border:1px">⇦</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇦</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇦</mo>
<mo style="border:1px" minsize="5">⇦</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21E8</mtext>
<mrow>
<mo style="border:1px">⇨</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇨</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇨</mo>
<mo style="border:1px" minsize="5">⇨</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21F0</mtext>
<mrow>
<mo style="border:1px">⇰</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇰</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇰</mo>
<mo style="border:1px" minsize="5">⇰</mo>
</mrow>
</mfrac>
<mspace linebreak="newline" indentalign="center"></mspace>
<mfrac style="border:1px">
<mtext>21EB</mtext>
<mrow>
<mo style="border:1px">⇫</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇫</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇫</mo>
<mo style="border:1px" minsize="5">⇫</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21EC</mtext>
<mrow>
<mo style="border:1px">⇬</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇬</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇬</mo>
<mo style="border:1px" minsize="5">⇬</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21ED</mtext>
<mrow>
<mo style="border:1px">⇭</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇭</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇭</mo>
<mo style="border:1px" minsize="5">⇭</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21EE</mtext>
<mrow>
<mo style="border:1px">⇮</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇮</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇮</mo>
<mo style="border:1px" minsize="5">⇮</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21EF</mtext>
<mrow>
<mo style="border:1px">⇯</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇯</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇯</mo>
<mo style="border:1px" minsize="5">⇯</mo>
</mrow>
</mfrac>
<mfrac style="border:1px">
<mtext>21F3</mtext>
<mrow>
<mo style="border:1px">⇳</mo>
<mo style="border:1px" minsize="1.2" maxsize="1.2" >⇳</mo>
<mo style="border:1px" minsize="2" maxsize="2">⇳</mo>
<mo style="border:1px" minsize="5">⇳</mo>
</mrow>
</mfrac>
</math>