Music

Music

So, yeah.

Any other questions?

Yeah.

The binary tree, should it be,

should it always have two successors?

Yes, a binary tree is a tree where a node has

either two successors or none.

Being wrongly impressed by that question

cost me an offer of a professorship

that was worse than the one that I have now,

so, oh well, but, so there are people around

who think that in a binary tree,

a node could have one successor,

but that's not possible.

So in a binary tree,

every node has either two or zero successors.

And the exercise says the node should be labeled

from the set.

Does this include the leaves or not?

Come again, what does it say exactly?

Should memorize this better.

There.

Okay, it says every node, right?

So that means interior nodes and leaves.

Yeah, we're going to get to the binary tree example today,

hopefully.

So, yeah.

More questions?

Following some gentle prodding,

I put the script online as far as it's done,

are mostly done or sort of underdone now,

so basically the first chapter,

the last end of it isn't reworked yet,

but you can take guesses from what you see there,

and close to finishing the first chapter,

and then I will replace that.

But you can already look at it as it stands now.

So, yeah, right.

Okay, let's try and recall where we left off

at the last session.

Laws for fold right.

At some point in the last session,

I think I decided to call fold right, fold left,

because some people said this was standard

in some programming language, did I?

I don't quite recall.

Or did I keep writing fold right?

Yeah, so, right, so I looked it up in the Haskell library,