So we fill our cognitive maps with these markers of meaning.

In Unit 5 the main new idea we introduced was how to measure cost.

The main new thing in Unit 3 was lists.

And then we introduced the hash table.

And so, in fact, what we've done is we, humanity, have started abstracting out.

The other thing we talked about in Unit 4 was how networks work.

And something very interesting is going on.

I'm going to formally tell you how to do that.

So let me stretch out that equation.

I wish to get to this point up here.

We can use a name to refer to some value.

Evans

In Unit 2 we introduced procedures.

We've seen lots and lots of examples of abstraction in this class.

And what's neat about mathematics, and what's neat about algebra in particular is we can focus on this abstraction. we can focus on the abstract here, we can manipulate the abstract here, and what we discover from these ideas, from these manipulations can then go and be reapplied to all of these other applications, to all of them.

This is a blue field it's actually an Yves Klein painting.

I'll address the planning problem at multiple levels of abstraction.

So the nth term, if this is, you know, if this is 10, it's going to be 1 plus 10 5's.

I go to the concept of The Lion King and I say, What is the essence of it?

We recognize them by the experiences and we abstract them into symbols.

That way, it makes it much easier to check if new statements invalidate a cached response.

So here is our glorious JavaScript interpreter, or at least the parts of it that you haven't already written.

A scientific theory comprises a collection of concepts, including abstractions of observable phenomena, expressed as quantifiable properties, together with rules (called scientific laws) that express relationships between observations of such concepts.

These are themes that aren't just pervasive throughout this course but are pervasive throughout all computer science.

And, then, when you have to draw it, that requires you to take an extra level of abstraction and figure out,

It must have been about an hour after this that the front door bell rang.

Let's just say, for the sake of argument, this is 1995.

And indeed, this kind of verbiage is not the exception, but the rule.

Then one last one. f of z.

Now, another kind of mind is the pattern thinker.

The first one is abstraction.

At that moment I became part of that biosphere.

It's a Boolean logical distinction rather than on this side a probabilistic distinction.

Well, we can go back to what we said before.

So as a running example, let's say we have a function of 2 variables, x and y, that's going to return their sum.

The spike would have to go infinitely high.

So in Unit 4 the main things we did were finish the search index by providing a way to produce an index of data.

You have mechanical systems.

You're not even capable of thinking in abstractions.

There are a few different types of graphics that you can use.

Another refinement is I can just take a taxi.

But we aren't done here.

I think you're satisfied that the area under this is going to be 1, regardless of what tau was.

For computing it's almost always the case that we want to use a digital abstraction where everything only represents 1 of 2 things.

Welcome to office hours for week 4.