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Last active August 29, 2015 13:57
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Lambda Calculator: Entering Special Symbols
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<h1>Lambda Calculator - Entering Special Symbols</h1>
<p>When using the Lambda Calculator, you will be asked to enter predicate
logic expressions. You can use the guide below to enter special symbols not
found on your keyboard.</p>
<h3>Constants and Variables</h3>
<ul>
<li>
<p>Primes can be entered with the apostrophe.</p>
<li>
<p>To use subscript notation to indicate the type of a constant or
variable, such as x<sub>e</sub>, use an underscore, e.g.
<pre>x_e
P_&lt;e,t&gt;</pre>
</p>
</ul>
<h3>Logical Connectives</h3>
<ul>
<li>
<p>To enter some of the logical connectives, you hit a particular key or
multiple keys on your keyboard but a different symbol appears on screen:</p>
<table>
<tr><th>Connective</th> <th>You Type</th></tr>
<tr>
<td style="text-align: center">¬</td>
<td style="text-align: center">~</td>
</tr>
<!--<tr>
<td style="text-align: center">=</td>
<td style="text-align: center">=</td>
</tr>-->
<tr>
<td style="text-align: center">≠</td>
<td style="text-align: center">!=</td>
</tr>
<tr>
<td style="text-align: center">∧</td>
<td style="text-align: center">&amp; or ^</td>
</tr>
<tr>
<td style="text-align: center">→</td>
<td style="text-align: center">-&gt;</td>
</tr>
<tr>
<td style="text-align: center">↔</td>
<td style="text-align: center">&lt;-&gt;</td>
</tr>
</table>
<li>
<p>Other connectives require that you hold down either the ALT key on
Windows and Linux computers or the CONTROL key on Macintosh computers
while pressing another key:</p>
<table>
<tr><th>Connective</th> <th>You Type</th></tr>
<tr>
<td style="text-align: center">∨</td>
<td style="text-align: center">ALT/CONTROL + V</td>
</tr>
</table>
</ul>
<h3>Quantifiers and Other Binders</h3>
<ul>
<li>
<p>Quantifiers and other binders require that you hold down either the ALT
key on Windows and Linux computers or the CONTROL key on Macintosh
computers while pressing another key:</p>
<table>
<tr><th>Quantifier</th> <th>You Type</th></tr>
<tr>
<td style="text-align: center">∃</td>
<td style="text-align: center">ALT/CONTROL + E</td>
</tr>
<tr>
<td style="text-align: center">∀</td>
<td style="text-align: center">ALT/CONTROL + A</td>
</tr>
<tr>
<td style="text-align: center">λ</td>
<td style="text-align: center">ALT/CONTROL + L</td>
</tr>
<tr>
<td style="text-align: center">ι</td>
<td style="text-align: center">ALT/CONTROL + I</td>
</tr>
</table>
</ul>
<h3>Sets</h3>
<ul>
<li>
<p>The set operators require that you hold down <b>SHIFT</b> and either
the ALT key on Windows and Linux computers or the CONTROL key on Macintosh
computers while pressing another key:</p>
<table>
<tr><th>Operator</th> <th>You Type</th></tr>
<tr>
<td style="text-align: center">∩</td>
<td style="text-align: center">ALT/CONTROL + SHIFT + ^</td>
</tr>
<tr><td style="text-align: center">∪</td>
<td style="text-align: center">ALT/CONTROL + SHIFT + V</td>
</tr>
<tr>
<td style="text-align: center">⊆</td>
<td style="text-align: center">ALT/CONTROL + &lt; (i.e. SHIFT+,)</td>
</tr>
<tr>
<td style="text-align: center">⊇</td>
<td style="text-align: center">ALT/CONTROL + &gt; (i.e. SHIFT+.)</td>
</tr>
</table>
<li>
<p>Some more complicated set operators require typing multiple keys:</p>
<table>
<tr><th>Operator</th> <th>You Type</th></tr>
<tr>
<td style="text-align: center">⊈</td>
<td style="text-align: center">!, then ALT/CONTROL + &lt;</td>
</tr>
<tr>
<td style="text-align: center">⊊</td>
<td style="text-align: center">type ALT/CONTROL + &lt; twice</td>
</tr>
<tr>
<td style="text-align: center">⊉</td>
<td style="text-align: center">!, then ALT/CONTROL + &gt;</td>
</tr>
<tr>
<td style="text-align: center">⊋</td>
<td style="text-align: center">type ALT/CONTROL + &gt; twice</td>
</tr>
</table>
<li>
<p>The empty set symbol ∅ can be entered by pressing ALT/CONTROL plus 0
(zero).</p>
</ul>
<h3>Numeric Connectives</h3>
<ul>
<li>
<p>Numeric connectives are available as well. You just type the usual
keys:</p>
<table>
<tr><th>Connective</th> <th>You Type</th></tr>
<tr>
<td style="text-align: center">⋅</td>
<td style="text-align: center">*</td> <td>(multiplication)</td>
</tr>
<tr>
<td style="text-align: center">&lt;</td>
<td style="text-align: center">&lt;</td>
</tr>
<tr>
<td style="text-align: center">≤</td>
<td style="text-align: center">&lt;=</td>
</tr>
<tr>
<td style="text-align: center">&gt;</td>
<td style="text-align: center">&gt;</td>
</tr>
<tr>
<td style="text-align: center">≥</td>
<td style="text-align: center">&gt;=</td>
</tr>
</table>
</ul>
</body>
</html>
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