The value space is the infinite set of integers greater than or equal to zero.
The lexical space is a finite-length sequence of decimal digits with an optional leading - or +.
<!-- schema -->
<xsd:element name="bank_balance"
type="xsd:nonNegativeInteger"/>
<!-- instance document -->
<bank_balance>32</bank_balance>
3.35.nonNegativeInteger
3.35.1.
The nonNegativeInteger datatype is derived from the integer type.