does the amount between the diastolic & systolic constitute arterial conditions .

I'm not really sure what you are asking, but systolic is when the ventricle contracts and diastolic is when the ventricle relaxes and fills with blood.

I mean does the number between dia & sys if its high mean the elasticity is good in arteries & veins

Interesting concept.

But I think of it more like the systolic represents the force of the heart's push and the diastolic the resistance (stiffness if you will) of the arterial system at rest...and perhaps even to the size of the arterioles and capillaries.

So hard to generalize because just changing the volume of liquid (blood) changes the whole equation. ANd of course hard work will raise systolic a LOT but not do much for diastolic.

Lot's of variables for a researcg paper...LOL