Wow, that is a big word for this site. I can only guess you are a mathmetician or play chess alot.

Sorry If I don't have your situation right but this is what I am thinking you are saying-

A= your character
X= enemy

_X
XAX
_X

You could move diagnally in this situation. The only requirement about moving is that you can't move into an enemy square unless you have something that removes that requirement like flight.

From the rule book-

The only time you cannot move diagonally past an enemy character is if there is a wall corner in one of the orthogonal squares.

So, if the situation looks like this:

_ Wall
A your character
X enemy character
E empty square

__E
XAX
EXE

If the 'A' character wanted to move to the square up and to the right, he would first have to kill the enemy to the right. However, as Boba pointed out, in your original question, if there are no walls or pits invovled, then there is no restriction on where you can move.

Also remember, that my example only applies when you have sharp corners involved. If it's a beveled wall corner, then you CAN move diagonally past it.