Original sentence: For all libertarians by defintion, the non-aggression principle is the central tenet of libertarianism, which is often premised by the principle of individual sovereignty or "self-ownership.It holds in its consequences that individuals should be allowed complete freedom of action as long as they do not infringe on the same freedom of others.Libertarianism is a  philosophy  which is completely based on one axiom - the non-aggression principle.Some sources give the the philospophy (to adress the political movement) a political attribute, but it is in the term anyhow a point of view
Edited sentence: For many libertarians, the non-aggression principle is the central tenet of libertarianism, which is often premised by the principle of individual sovereignty or "self-ownership.Libertarianism is a  political philosophy (involving fundamental questions about the state, government, politics, property, law and the enforcement of a legal code by authority)  that holds that individuals should be allowed complete freedom of action as long as they do not infringe on the same freedom of others