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      <header alignment="Center" color="#a9a9a9">&amp;[DATE] &amp;[TIME] - &amp;[FILENAME]</header>
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          <p style="font-weight: bold; color: #800000; font-size: 12px;">Piecewise continue functions</p>
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          <p>|<br />|<br />|<br />|<br />|<br />|<br />|<br />|<br />|<br />|<br />|</p>
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          <p>Notice that </p>
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          <e type="operand">4</e>
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          <e type="operand" style="string">0.99.7822.147</e>
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          <p>Redefine sign as</p>
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          <e type="operand">x#</e>
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          <e type="operand">x#</e>
          <e type="operand" style="unit">ε</e>
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          <e type="operand">1</e>
          <e type="operand">1</e>
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          <p>Changes to</p>
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          <e type="operand">2</e>
          <e type="operand">x</e>
          <e type="operand" style="unit">ε</e>
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          <e type="bracket">(</e>
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          <p>with</p>
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          <p>... for now.</p>
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          <p>and ...</p>
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          <p>Shorthand</p>
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          <p style="font-weight: bold; color: #408080;">Example</p>
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          <p>Let</p>
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          <e type="operand">x</e>
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          <p>You can try to define without line too. (but f needs it fin integrals and "zero" case)</p>
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          <p>This is the correct way to define a piecewise function.</p>
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          <p>We have only two reds for f:</p>
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        <input>
          <e type="operand">xo</e>
          <e type="function" args="1">g</e>
          <e type="operand">xo</e>
          <e type="function" args="2">diff</e>
        </input>
        <result action="numeric">
          <e type="operand">#</e>
        </result>
      </math>
    </region>
    <region left="531" top="918" width="114" height="44" color="#000000" fontSize="10">
      <math error="2">
        <input>
          <e type="operand">xo</e>
          <e type="function" args="1">h</e>
          <e type="operand">xo</e>
          <e type="function" args="2">diff</e>
        </input>
        <result action="numeric">
          <e type="operand">#</e>
        </result>
      </math>
    </region>
    <region left="54" top="981" width="407" height="48" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">x</e>
          <e type="function" args="1">f</e>
          <e type="operand">x</e>
          <e type="function" args="2">Jacob</e>
        </input>
        <result action="symbolic">
          <e type="operand">x</e>
          <e type="operand">x</e>
          <e type="operator" args="1">-</e>
          <e type="function" args="1">abs</e>
          <e type="operator" args="2">-</e>
          <e type="operand">3</e>
          <e type="operand">2</e>
          <e type="operand">3</e>
          <e type="operator" args="1">-</e>
          <e type="operand">x</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operator" args="2">*</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operand">x</e>
          <e type="operand">x</e>
          <e type="function" args="1">abs</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operator" args="2">*</e>
          <e type="operator" args="2">+</e>
          <e type="operand">2</e>
          <e type="operand">x</e>
          <e type="operator" args="2">*</e>
          <e type="operator" args="2">/</e>
          <e type="operand">1</e>
          <e type="operand">1</e>
          <e type="function" args="3">mat</e>
        </result>
      </math>
    </region>
    <region left="306" top="1035" width="147" height="28" color="#000000" fontSize="10">
      <math error="2">
        <input>
          <e type="operand">x</e>
          <e type="function" args="1">g</e>
          <e type="operand">x</e>
          <e type="function" args="2">Jacob</e>
        </input>
        <result action="symbolic">
          <e type="operand">#</e>
        </result>
      </math>
    </region>
    <region left="531" top="1035" width="141" height="28" color="#000000" fontSize="10">
      <math error="17">
        <input>
          <e type="operand">x</e>
          <e type="function" args="1">h</e>
          <e type="operand">x</e>
          <e type="function" args="2">Jacob</e>
        </input>
        <result action="symbolic">
          <e type="operand">#</e>
        </result>
      </math>
    </region>
    <region left="54" top="1071" width="117" height="69" color="#000000" fontSize="10">
      <math error="2" errorLocation="0">
        <input>
          <e type="operand">ξ</e>
          <e type="function" args="1">f</e>
          <e type="operand">ξ</e>
          <e type="operand">2</e>
          <e type="operator" args="1">-</e>
          <e type="operand">2</e>
          <e type="function" args="4">int</e>
        </input>
        <result action="numeric">
          <e type="operand">#</e>
        </result>
      </math>
    </region>
    <region left="306" top="1071" width="117" height="69" color="#000000" fontSize="10">
      <math error="2" errorLocation="0">
        <input>
          <e type="operand">ξ</e>
          <e type="function" args="1">g</e>
          <e type="operand">ξ</e>
          <e type="operand">2</e>
          <e type="operator" args="1">-</e>
          <e type="operand">2</e>
          <e type="function" args="4">int</e>
        </input>
        <result action="numeric">
          <e type="operand">#</e>
        </result>
      </math>
    </region>
    <region left="531" top="1071" width="170" height="69" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">ξ</e>
          <e type="function" args="1">h</e>
          <e type="operand">ξ</e>
          <e type="operand">2</e>
          <e type="operator" args="1">-</e>
          <e type="operand">2</e>
          <e type="function" args="4">int</e>
        </input>
        <result action="numeric">
          <e type="operand">1.3333</e>
          <e type="operator" args="1">-</e>
        </result>
      </math>
    </region>
    <region left="18" top="1152" width="183" height="40" color="#000000" fontSize="10">
      <text lang="eng" width="174" fontFamily="Consolas" fontSize="10">
        <content>
          <p>We can correct the two errors for f with</p>
        </content>
      </text>
    </region>
    <region left="225" top="1152" width="140" height="24" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand" style="unit">ε</e>
          <e type="operand">0.00000000001</e>
          <e type="operator" args="2">:</e>
        </input>
      </math>
    </region>
    <region left="396" top="1152" width="170" height="69" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">ξ</e>
          <e type="function" args="1">f</e>
          <e type="operand">ξ</e>
          <e type="operand">2</e>
          <e type="operator" args="1">-</e>
          <e type="operand">2</e>
          <e type="function" args="4">int</e>
        </input>
        <result action="numeric">
          <e type="operand">1.3333</e>
          <e type="operator" args="1">-</e>
        </result>
      </math>
    </region>
    <region left="594" top="1152" width="146" height="56" color="#000000" fontSize="10">
      <text lang="eng" fontFamily="Consolas" fontSize="10">
        <content>
          <p>Notice that all previous values remains unchanged.</p>
        </content>
      </text>
    </region>
    <region left="225" top="1197" width="67" height="26" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">0</e>
          <e type="function" args="1">f</e>
        </input>
        <result action="numeric">
          <e type="operand">1</e>
        </result>
      </math>
    </region>
    <region left="18" top="1233" width="146" height="24" color="#000000" fontSize="10">
      <text lang="eng" fontFamily="Consolas" fontSize="10">
        <content>
          <p>Also, only for f: </p>
        </content>
      </text>
    </region>
    <region left="207" top="1233" width="44" height="24" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand" style="unit">ε</e>
          <e type="operand">0</e>
          <e type="operator" args="2">:</e>
        </input>
      </math>
    </region>
    <region left="432" top="1251" width="322" height="56" color="#000000" fontSize="10">
      <text lang="eng" width="307" fontFamily="Consolas" fontSize="10">
        <content>
          <p>As shown, Maple recognize the behavior of f, and this is why I say that it's the only "well defined" piecewise function.</p>
        </content>
      </text>
    </region>
    <region left="54" top="1269" width="350" height="48" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">x</e>
          <e type="function" args="1">df</e>
          <e type="operand">x</e>
          <e type="function" args="1">f</e>
          <e type="operand">x</e>
          <e type="function" args="2">diff</e>
          <e type="operand">Heaviside</e>
          <e type="function" args="2">convert</e>
          <e type="function" args="1">maple</e>
          <e type="operator" args="2">:</e>
        </input>
      </math>
    </region>
    <region left="90" top="1323" width="85" height="26" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">xo</e>
          <e type="function" args="1">df</e>
        </input>
        <result action="numeric">
          <e type="operand">1</e>
        </result>
      </math>
    </region>
    <region left="288" top="1323" width="183" height="43" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">x</e>
          <e type="function" args="1">df</e>
        </input>
        <result action="symbolic">
          <e type="operand">x</e>
          <e type="operand">x</e>
          <e type="function" args="1">abs</e>
          <e type="operator" args="2">+</e>
          <e type="operand">6</e>
          <e type="operator" args="2">-</e>
          <e type="operand">2</e>
          <e type="operand">x</e>
          <e type="operator" args="2">*</e>
          <e type="operator" args="2">+</e>
          <e type="operand">2</e>
          <e type="operator" args="2">/</e>
        </result>
      </math>
    </region>
    <region left="531" top="1368" width="205" height="40" color="#000000" fontSize="10">
      <text lang="eng" fontFamily="Consolas" fontSize="10">
        <content>
          <p>Same thing, more or less, with Maxima.</p>
        </content>
      </text>
    </region>
    <region left="54" top="1377" width="366" height="43" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">x</e>
          <e type="function" args="1">adf</e>
          <e type="operand">x</e>
          <e type="function" args="1">f</e>
          <e type="operand">x</e>
          <e type="function" args="2">int</e>
          <e type="operand">Heaviside</e>
          <e type="function" args="2">convert</e>
          <e type="function" args="1">maple</e>
          <e type="operator" args="2">:</e>
        </input>
      </math>
    </region>
    <region left="90" top="1431" width="213" height="26" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">2</e>
          <e type="function" args="1">adf</e>
          <e type="operand">2</e>
          <e type="operator" args="1">-</e>
          <e type="function" args="1">adf</e>
          <e type="operator" args="2">-</e>
        </input>
        <result action="numeric">
          <e type="operand">1.3333</e>
          <e type="operator" args="1">-</e>
        </result>
      </math>
    </region>
    <region left="369" top="1431" width="367" height="49" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">x</e>
          <e type="function" args="1">adf</e>
        </input>
        <result action="symbolic">
          <e type="operand">x</e>
          <e type="operand">3</e>
          <e type="operand">x</e>
          <e type="operand">2</e>
          <e type="operand">1</e>
          <e type="operator" args="1">-</e>
          <e type="operand">x</e>
          <e type="operator" args="2">+</e>
          <e type="operand">x</e>
          <e type="function" args="1">abs</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operator" args="2">*</e>
          <e type="operator" args="2">-</e>
          <e type="bracket">(</e>
          <e type="operator" args="2">*</e>
          <e type="operand">x</e>
          <e type="operand">x</e>
          <e type="function" args="1">abs</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operand">x</e>
          <e type="operator" args="2">*</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operator" args="2">*</e>
          <e type="operand">6</e>
          <e type="operator" args="2">/</e>
        </result>
      </math>
    </region>
    <region left="18" top="1494" width="747" height="40" color="#000000" fontSize="10">
      <text lang="eng" fontFamily="Consolas" fontSize="10">
        <content>
          <p>
            <span style="font-weight: bold;">Conclussion</span>: Notice that I only redefine <span style="font-weight: bold;">sign</span> for get correct answers for all the usual numeric and symbolics procedures. The errors related with cases could be hard to leave:</p>
        </content>
      </text>
    </region>
    <region left="90" top="1539" width="114" height="44" color="#000000" fontSize="10">
      <math error="2">
        <input>
          <e type="operand">xo</e>
          <e type="function" args="1">h</e>
          <e type="operand">xo</e>
          <e type="function" args="2">diff</e>
        </input>
        <result action="numeric">
          <e type="operand">#</e>
        </result>
      </math>
    </region>
    <region left="297" top="1548" width="250" height="24" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">lastError</e>
        </input>
        <result action="numeric">
          <e type="operand" style="string">xo - not defined.</e>
        </result>
      </math>
    </region>
    <region left="90" top="1593" width="177" height="28" color="#000000" fontSize="10">
      <math error="17">
        <input>
          <e type="operand">x</e>
          <e type="function" args="1">h</e>
          <e type="operand">x</e>
          <e type="operand">xo</e>
          <e type="function" args="3">roots</e>
        </input>
        <result action="numeric">
          <e type="operand">#</e>
        </result>
      </math>
    </region>
    <region left="297" top="1593" width="362" height="24" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">lastError</e>
        </input>
        <result action="numeric">
          <e type="operand" style="string">Inequalities are not supported.</e>
        </result>
      </math>
    </region>
    <region left="90" top="1629" width="141" height="28" color="#000000" fontSize="10">
      <math error="17">
        <input>
          <e type="operand">x</e>
          <e type="function" args="1">h</e>
          <e type="operand">x</e>
          <e type="function" args="2">Jacob</e>
        </input>
        <result action="symbolic">
          <e type="operand">#</e>
        </result>
      </math>
    </region>
    <region left="297" top="1638" width="362" height="24" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">lastError</e>
        </input>
        <result action="numeric">
          <e type="operand" style="string">Inequalities are not supported.</e>
        </result>
      </math>
    </region>
    <region left="18" top="1674" width="388" height="24" color="#000000" fontSize="10">
      <text lang="eng" fontFamily="Consolas" fontSize="10">
        <content>
          <p>Also we can do some algebra with f, but not with h:</p>
        </content>
      </text>
    </region>
    <region left="72" top="1710" width="529" height="45" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">x</e>
          <e type="function" args="1">h</e>
          <e type="operand">x</e>
          <e type="operator" args="1">-</e>
          <e type="function" args="1">h</e>
          <e type="operator" args="2">-</e>
        </input>
        <result action="symbolic">
          <e type="operand">1</e>
          <e type="operand">x</e>
          <e type="operand">3</e>
          <e type="operator" args="1">-</e>
          <e type="operand">x</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operator" args="2">*</e>
          <e type="operator" args="2">+</e>
          <e type="operand">x</e>
          <e type="operand">0</e>
          <e type="operator" args="2">&gt;</e>
          <e type="operand">1</e>
          <e type="operand">x</e>
          <e type="operator" args="2">+</e>
          <e type="function" args="3">cases</e>
          <e type="operand">1</e>
          <e type="operand">x</e>
          <e type="operand">3</e>
          <e type="operand">x</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operator" args="2">*</e>
          <e type="operator" args="2">+</e>
          <e type="operand">x</e>
          <e type="operator" args="1">-</e>
          <e type="operand">0</e>
          <e type="operator" args="2">&gt;</e>
          <e type="operand">1</e>
          <e type="operand">x</e>
          <e type="operator" args="2">-</e>
          <e type="function" args="3">cases</e>
          <e type="operator" args="2">-</e>
        </result>
      </math>
    </region>
    <region left="72" top="1764" width="616" height="45" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">x</e>
          <e type="function" args="1">f</e>
          <e type="operand">x</e>
          <e type="operator" args="1">-</e>
          <e type="function" args="1">f</e>
          <e type="operator" args="2">-</e>
        </input>
        <result action="symbolic">
          <e type="operand">1</e>
          <e type="operand">x</e>
          <e type="operand">3</e>
          <e type="operator" args="1">-</e>
          <e type="operand">x</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operator" args="2">*</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operand">x</e>
          <e type="operand">x</e>
          <e type="function" args="1">abs</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operator" args="2">*</e>
          <e type="operator" args="1">-</e>
          <e type="operand">x</e>
          <e type="operand">2</e>
          <e type="operand">x</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operator" args="2">*</e>
          <e type="operand">x</e>
          <e type="operand">x</e>
          <e type="operator" args="1">-</e>
          <e type="function" args="1">abs</e>
          <e type="operator" args="2">-</e>
          <e type="bracket">(</e>
          <e type="operator" args="2">*</e>
          <e type="operator" args="2">+</e>
          <e type="operand">1</e>
          <e type="operand">x</e>
          <e type="operator" args="2">-</e>
          <e type="bracket">(</e>
          <e type="operand">x</e>
          <e type="operand">x</e>
          <e type="function" args="1">abs</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operator" args="2">*</e>
          <e type="operator" args="2">+</e>
          <e type="operand">2</e>
          <e type="operand">x</e>
          <e type="operator" args="2">*</e>
          <e type="operator" args="2">/</e>
          <e type="operator" args="1">-</e>
        </result>
      </math>
    </region>
    <region left="18" top="1809" width="490" height="24" color="#000000" fontSize="10">
      <text lang="eng" fontFamily="Consolas" fontSize="10">
        <content>
          <p>and with SMath having a little more skills, we can se things like</p>
        </content>
      </text>
    </region>
    <region left="72" top="1845" width="347" height="30" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">x</e>
          <e type="function" args="1">f</e>
          <e type="operand">x</e>
          <e type="operator" args="1">-</e>
          <e type="function" args="1">f</e>
          <e type="operator" args="2">-</e>
          <e type="function" args="1">simplify</e>
          <e type="function" args="1">maple</e>
        </input>
        <result action="symbolic">
          <e type="operand">x</e>
          <e type="operand">2</e>
          <e type="operator" args="1">-</e>
          <e type="operand">x</e>
          <e type="function" args="1">abs</e>
          <e type="operator" args="2">+</e>
          <e type="bracket">(</e>
          <e type="operator" args="2">*</e>
        </result>
      </math>
    </region>
    <region left="9" top="1890" width="732" height="40" color="#000000" fontSize="10">
      <text lang="eng" fontFamily="Consolas" fontSize="10">
        <content>
          <p>
            <span style="font-weight: bold;">Issues using Φ</span>: First of all, time: with Φ the program evaluate both cases, with if only one. And maybe some errors when evaluate the body if it isn't the case, like in.</p>
        </content>
      </text>
    </region>
    <region left="162" top="1944" width="82" height="41" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">y.1</e>
          <e type="operand">1</e>
          <e type="operand">x</e>
          <e type="operand">1</e>
          <e type="operator" args="2">+</e>
          <e type="operator" args="2">/</e>
          <e type="operator" args="2">:</e>
        </input>
      </math>
    </region>
    <region left="288" top="1944" width="80" height="26" color="#000000" fontSize="10">
      <math error="57" errorLocation="2">
        <input>
          <e type="operand">1</e>
          <e type="operator" args="1">-</e>
          <e type="function" args="1">f</e>
        </input>
        <result action="numeric">
          <e type="operand">#</e>
        </result>
      </math>
    </region>
    <region left="414" top="1944" width="80" height="26" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">1</e>
          <e type="operator" args="1">-</e>
          <e type="function" args="1">g</e>
        </input>
        <result action="numeric">
          <e type="operand">0</e>
        </result>
      </math>
    </region>
    <region left="558" top="1944" width="80" height="26" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">1</e>
          <e type="operator" args="1">-</e>
          <e type="function" args="1">h</e>
        </input>
        <result action="numeric">
          <e type="operand">0</e>
        </result>
      </math>
    </region>
    <region left="9" top="1998" width="256" height="24" color="#000000" fontSize="10">
      <text lang="eng" fontFamily="Consolas" fontSize="10">
        <content>
          <p>and that's can't be solved with ε</p>
        </content>
      </text>
    </region>
    <region left="279" top="1998" width="140" height="24" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand" style="unit">ε</e>
          <e type="operand">0.00000000001</e>
          <e type="operator" args="2">:</e>
        </input>
      </math>
    </region>
    <region left="441" top="1998" width="80" height="26" color="#000000" fontSize="10">
      <math error="57" errorLocation="2">
        <input>
          <e type="operand">1</e>
          <e type="operator" args="1">-</e>
          <e type="function" args="1">f</e>
        </input>
        <result action="numeric">
          <e type="operand">#</e>
        </result>
      </math>
    </region>
    <region left="549" top="1998" width="197" height="40" color="#000000" fontSize="10">
      <text lang="eng" fontFamily="Consolas" fontSize="10">
        <content>
          <p>but isn't continue then. (see the title of this)</p>
        </content>
      </text>
    </region>
    <region left="9" top="2043" width="747" height="40" color="#000000" fontSize="10">
      <text lang="eng" fontFamily="Consolas" fontSize="10">
        <content>
          <p>Finally, there are antoher "kind" of piecewise functions, where the test is foncion of the variable too, and ... well, there are a lot of more cases.</p>
        </content>
      </text>
    </region>
    <region left="9" top="2097" width="60" height="24" color="#000000" fontSize="10">
      <math>
        <input>
          <e type="operand">Alvaro</e>
        </input>
      </math>
    </region>
  </regions>
</worksheet>