The farthest paths that have been explored, we call the frontier.

So let's write down those three components.

It's final because once we reach it, it's limitless.

It starts off by initializing the frontier to be the path consisting of only the initial states, and then it goes into a loop in which it first checks to see do we still have anything left in the frontier?

I expected it.

Which we have come to regard as natural.

I want to spend most of my time on this part of the world.

And we pop that empty path off.

So 140 is the lowest.

And that's the cheapest, so this one gets expanded.

The answer is this one. Two twenty is less than 229 or 239.

A final frontier begins in this hall.

This one, this one, and this one.

And only a few years later in 1986

Isaiah Berlin put it this way

The answer is that we're not done yet, because the algorithm works by doing the goal test, when we take a path off the front tier, not when we put a path on the front tier.

True, we have added a path that ends in Bucharest, but the goal test isn't applied when we add a path to the frontier.

Again, we don't stop here just because we put a path onto the front tier, we put it there, we don't apply the goal test next, but, now we go back to the front tier, and it turns out that this 418 is the lowest cost path on the front tier.

These are all points on you as a hunter gatherer, on your production possibilities frontier.

Now Tree Search represents a whole family of algorithms, and where you get the family resemblance is that they're all looking at the frontier, copying items off and and looking to see if their goal tests, but where you get the difference is right here, in the choice of how you're going to expand the next item on the frontier, which path do we look at first, and we'll go through different sets of algorithms that make different choices for which path to look at first.

Now, here's another representation of the search space and what's happening is as we start to explore the state, we keep track of the frontier, which is the set of states that are at the end of the paths that we haven't explored yet, and behind that frontier is the set of explored states, and ahead of the frontier is the unexplored states.

Now it could be called shortest first search because what it does is always choose of the frontier one of the paths that hadn't been considered yet that's the shortest possible.

length 0, starting in the start state, and that's the only path in the frontier so it's the shortest one so we pick it, and then we expand it, and we add in all the paths that result from applying all the possible actions.

And so at last mankind began the conquest and colonization of deep space.

Now let's turn to two countries,

Azerbaijan was a forgotten corner of the Caucuses, but now with the Baku Tbilisi Ceyhan pipeline into Turkey, it has rebranded itself as the frontier of the west.

Male narrator

Traitor, traitor, traitor.

Great Britain, USA

And I believe that if you are a beneficiary of that civilization it is your duty too.

Instead, we just continue in the normal way and choose the node on the front tier which has the lowest value.

An Englishman is an alien in the United States.

The superstars of climate change in 2006

like the ones between modernity and tradition,

It labels developing countries, I can read from the list here developing countries

If we're talking about national security problems, maybe it's the Secretary of State, maybe it's the Secretary of Defense, the Director of National Intelligence, maybe the ambassador to the United Nations, or somebody else who they think is going to know more about the particular problem.

One of the things that we did with the Ansari X PRlZE was take the challenge on that risk is OK, you know.

Mexico is a nation that borders the United States.

Mexico is a country whose borders adjoin with those of the United States.

The European Union, same thing.

Well, you were the one who caused the problem.

Around the same time,

country

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