A>B and B > C then A > C

This is transitive.

Deetailed link is here: http://en.wikipedia.org/wiki/Transitive_relation

By the way, set inclusion and equality are transitive.

Any issues on the pic?
Go all the way http://tootrivial.blogspot.in/2014/02/intension-vs-extension.html

நீயே உனக்கு என்றும் நிகரானவன்

From Wiki,
a reflexive relation is a binary relation on a set for which every element is related to itself. In other words, a relation ~ on a set S is reflexive when x ~ x holds true for every x in S.^[1][2] An example of a reflexive relation is the relation "is equal to" on the set of real numbers, since every real number is equal to itself. A reflexive relation is said to have the reflexive property or is said to possess reflexivity.

Intension vs Extension

A set is determined by its extension. Is that so?

http://math.stackexchange.com/questions/668638/axiom-of-extensionality-why-not-called-equality