Thanks Henry, your solution worked perfectly for me. 
Thanks for all replies.

-Saravanan

-----Original Message-----
From: xmlschema-dev-request@w... [mailto:xmlschema-dev-request@w...] On Behalf Of ht@i...
Sent: Wednesday, May 05, 2004 11:29 AM
To: Veerappan Saravanan-ESV007
Cc: noah_mendelsohn@u...; xmlschema-dev@w...
Subject: Re: Unique Particle Attribution



Not sure what you actually want.

If what you wrote is really what you mean, which I _think_ is that all and only the following are allowed

   aaaaab
   aaaab
   aaab
   aab
   ab
   abb
   abbb
   abbbb
   abbbbb
   
then all you need is

  <xs:sequence>
   <xs:element ref="a"/>
   <xs:choice>
    <xs:element ref="b" maxOccurs="5"/>
    <xs:sequence>
     <xs:element ref="a" maxOccurs="4"/>
     <xs:element ref="b"/>
    </xs:sequence>
   </xs:choice>
  </xs:sequence>

If only

 abbbbb
 ab
 aaaaab

are allowed, that can be done as

 <xs:sequence>
   <xs:element ref="a"/>
   <xs:choice>
    <xs:sequence>
     <xs:element ref="b"/>
     <xs:sequence minOccurs="0">
      <xs:element ref="b" maxOccurs="4" minOccurs="4"/>
     </xs:sequence>
    </xs:sequence>
    <xs:sequence>
     <xs:element ref="a" maxOccurs="4" minOccurs="4"/>
     <xs:element ref="b"/>
    </xs:sequence>
   </xs:choice>
  </xs:sequence>

ht
-- 
 Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
                     Half-time member of W3C Team
    2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
            Fax: (44) 131 650-4587, e-mail: ht@i...
                   URL: http://www.ltg.ed.ac.uk/~ht/
[mail really from me _always_ has this .sig -- mail without it is forged spam]

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