tns appearing in Web Services schema

Question

I'm using JAX-WS for running some sample Web services. After publishing the web services, when I typed the WSDL URL, I could see the WSDL document. WSDL document refers a Schema document that goes like this:

<xs:schema version="1.0" targetNamespace="http://ts.ch01/">
<xs:element name="getTimeAsElapsed" type="tns:getTimeAsElapsed"/>
<xs:element name="getTimeAsElapsedResponse" type="tns:getTimeAsElapsedResponse"/>
<xs:element name="getTimeAsString" type="tns:getTimeAsString"/>
<xs:element name="getTimeAsStringResponse" type="tns:getTimeAsStringResponse"/>
−
<xs:complexType name="getTimeAsString">
<xs:sequence/>
</xs:complexType>
−
<xs:complexType name="getTimeAsStringResponse">
−
<xs:sequence>
<xs:element name="return" type="xs:string" minOccurs="0"/>
</xs:sequence>
</xs:complexType>
−
<xs:complexType name="getTimeAsElapsed">
<xs:sequence/>
</xs:complexType>
−
<xs:complexType name="getTimeAsElapsedResponse">
−
<xs:sequence>
<xs:element name="return" type="xs:long"/>
</xs:sequence>
</xs:complexType>
</xs:schema>

My question is why is 'tns' appearing in the element declaration? For example:

<xs:element name="getTimeAsElapsed" type="tns:getTimeAsElapsed"/>

I've nowhere is the schema document seeing 'tns' to be declared as namespace prefix, the schema document simply starts with

<xs:schema version="1.0" targetNamespace="http://ts.ch01/">

Then why 'tns' is appearing when referencing other elements? Is this by default behaviour of XML schema generated by JAX-WS?

Solution

As per w3, tns means "this namespace", referring to the current document.

Source: https://www.w3.org/TR/wsdl.html#_notational