SOAP WS Standards?

[Mohamed Farouk]

In Study Guide from MZ
Page 15 it says as below I cannot understand properly can someone explain plz>>>>>
This section defines rules for serialization of a graph of typed objects.It operates on two levels.

First, given a schema in any notation consistent with the type system described, a schema for an XML grammar may be constructed.

I thaught schema is the grammer for XML so what is the above items means?

Second, given a type-system schema and a particular graph of values conforming to that schema, an XML instance may be constructed.

Does it mean given a schema and an XML instance another instance is created?

XSD + XSI = XML?

In reverse, given an XML instance produced in accordance with these rules, and given also the original schema, a copy of the original value graph may be constructed

XSI + XSD = VALUE GRAPH?

So quite confused what is value grapth , XSI , XML and XSD how do they relate?