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15

First Steps in Lojban

Lesson 15. Copulas: me and du

Koshon
Koshon

Let's take a break from tags for a bit and talk about copulas—the "be-verbs." Specifically, how to say things like “A is B” when B isn't just a simple predicate.

Sora
Sora

You mean like when we're setting two things equal to each other?

Koshon
Koshon

Something like that. Remember, we already have sentences like ti mlatu (this is a cat) or ti bloti (this is a boat), which don't need any extra words for "is."

Sora
Sora

True. But I still don't know how to say something like "This is Sora" or "That is the specific boat we were talking about."

Koshon
Koshon

Good point! Lojban handles this in a few ways. Let's start with me.

me
Before a sumti: selbri meaning “x1 is among / identical with [that sumti]” (see dictionary for full places).
Koshon
Koshon

When you say A me B, you're saying one of three things: that A is among the items in group B, that A is identical to B, or that A's group is a subset of B's group.

Basically, think about "the things A points at" and "the things B points at":

  • If every thing A refers to is also something B refers to, you're using me (it's either a member of B or a sub-group of B).
  • If A and B refer to exactly the same set of things, that's identity (co-reference).

In simple terms: everything that is A is also B.

If I tried to draw that “A sits inside B” idea, it might look like this:

**me** (overlap / inclusion)
**me** (overlap / inclusion)
Rough picture: what A refers to is covered by what B refers to.

For example:

lo vi nanmu cu me lo dinju cikre This man is one of the building-repair crew.

Koshon
Koshon

Be careful! me is not used to talk about literal parts of a whole (like a wheel being part of a car). For that, we use the word pagbu.

lo vi klupe cu pagbu le minji This screw is a part of the machine.

Sora
Sora

Got it. pagbu for the "part-of" relationship, and me for "membership" or overlap.

Koshon
Koshon

If you want to express strict identity (A and B are exactly the same thing), we use the word du.

du
x1 is identical to x2

ti du la .mikan. This is Mika.

tu du le bloti That is the boat.

du, like me, is a cmavo that can act as selbri.

True or false

Pick whether each statement is true or false according to the lesson.

  1. me is basically glossed as “one/some among …”.

  2. du expresses identity and can be used as a selbri even though it is a cmavo.

  3. If A du B, then A me B always holds too.