I am thinking of how suitable knowledge graphs such as "Google Knowledge Graph", "WordNet", "Yago", or "FreeBase" is for representing facts including a preposition or adjective.
For example, "Obama has a daughter" can clearly be represented by node and link relations. "Obama" and "daughter" are nodes. "has a" is a link.
However, I can not find a way to represent a sentence with a preposition or adjective by googling by several keywords.
Suppose you have a fact that "Obama has a white dog in whitehouse", it seems impossible to be represented by graph structures. Obama's dog is white, bat not all dog is white. Also, Obama's dog is kept in whitehouse, but not all dog is.
My first question is whether knowledge graph can represent this kind of fact or not. My second question is how knowledge graph can do this, if the first answer is yes.
You'd represent this is a series of facts. For example:
barackObama owns fido
fido isA dog
fido livesIn theWhiteHouse
fido hasFurColour white
i.e. you have a specific node in your graph which represents the specific object, and then assert further facts about that object. Similarly, while you could assert a single fact "barackObama hasA daughter", you'd probably assert a number of facts linking the two nodes "barackObama" and "maliaObama".
As with everything else, there is no one "right" representation of your data - it varies depending on the problem you're trying to solve.