# Show that inclusion is an order relation in the set of all sets

Not sure how to answer this question.

"Show that inclusion is an order relation in the set of all sets"


My understanding is that I have to show that inclusion on the set of all sets, is reflexive, anti-symmetric and transitive. Is this right? I'm not sure why the set of all sets is included in the question, but it must be there for a reason?

What is the difference between "order relation" and "partial order"?

• I think there may be more than one type of def'n of partial order. In the set-theoretic topic of Forcing, a poset (short for partially ordered set) is a set with a binary relation $\leq$ that is reflexive and transitive. It is allowable in Forcing to have a poset in which $x\leq y\leq x$ and $x\ne y$ for some $x,y.$ – DanielWainfleet Mar 26 '17 at 18:11