<?xml version="1.0" encoding="UTF-8"?>

<LogicDiagram id="ch3apa" source="ch3apa.jpg">

  <Nodes>

    <Decision id="D1" name="TWA-MSK-ID = THIS-PGMS-MSK?"/>
    <Decision id="D2" name="DUP-FUNCTION?"/>
    <Decision id="D3" name="SEE-FUNCTION?"/>
    <Decision id="D4" name="SKEY = TWA-LAST-KEY?"/>
    <Decision id="D5" name="SFUNCT = TWA-LAST-FUNCT?"/>

    <Action id="A1" name="ASK OPERATOR TO GIVE NEW KEY"/>

    <Decision id="D6" name="CHG- or DEL-FUNCTION?"/>
    <Decision id="D7" name="TWA-LAST-FUNCT was SEE-FUNCTION?"/>

    <Terminal id="T1" name="NEW-TRANSACTION-MODE"/>
    <Terminal id="T2" name="CONTINUATION-MODE"/>

  </Nodes>

  <Edges>

    <!-- Primary validation chain -->
    <Edge from="D1" to="D2" condition="YES"/>
    <Edge from="D1" to="T1" condition="NO"/>

    <Edge from="D2" to="T1" condition="YES"/>
    <Edge from="D2" to="D3" condition="NO"/>

    <Edge from="D3" to="T1" condition="YES"/>
    <Edge from="D3" to="D4" condition="NO"/>

    <Edge from="D4" to="T1" condition="YES"/>
    <Edge from="D4" to="D5" condition="NO"/>

    <Edge from="D5" to="T1" condition="YES"/>
    <Edge from="D5" to="T1" condition="NO"/>

    <!-- Key change / continuation branch -->
    <Edge from="D4" to="A1" condition="NO"/>

    <Edge from="A1" to="D6"/>

    <Edge from="D6" to="T2" condition="YES"/>
    <Edge from="D6" to="D7" condition="NO"/>

    <Edge from="D7" to="T2" condition="YES"/>
    <Edge from="D7" to="T1" condition="NO"/>

  </Edges>

  <Summary>

    <Outcome name="NEW-TRANSACTION-MODE"/>
    <Outcome name="CONTINUATION-MODE"/>

    <Observation>
      Most evaluation paths resolve to NEW-TRANSACTION-MODE unless
      a continuation condition (CHG/DEL + SEE context) is satisfied.
    </Observation>

  </Summary>

</LogicDiagram>