## Chapter 10: Imaginary Journeys: The Lojban Space/Time Tense System

### 17. Tensed logical connectives

The Lojban tense system interacts with the Lojban logical connective system. That system is a separate topic, explained in Chapter 14 and touched on only in summary here. By the rules of the logical connective system, ✥17.1 through 17.3 are equivalent in meaning:

```✥17.1    la teris. satre le mlatu
.ije la teris. satre le ractu
Terry strokes the cat.
And Terry strokes the rabbit.

✥17.2 la teris. satre le mlatu gi'e satre le ractu
Terry strokes the cat and strokes the rabbit.

✥17.3 la teris. satre le mlatu .e le ractu
Terry strokes the cat and the rabbit.```

Suppose we wish to add a tense relationship to the logical connective “and”? To say that Terry strokes the cat and later strokes the rabbit, we can combine a logical connective with a tense connective by placing the logical connective first, then the tense, and then the cmavo “bo”, thus:

```✥17.4    la teris. satre le mlatu
.ijebabo la teris. satre le ractu
Terry strokes the cat.
And then Terry strokes the rabbit.```

```✥17.5    la teris. satre le mlatu gi'ebabo satre le ractu
Terry strokes the cat, and then strokes the rabbit.```

```✥17.6    la teris. satre le mlatu .ebabo le ractu
Terry strokes the cat and then the rabbit.```

✥17.4 through 17.6 are equivalent in meaning. They are also analogous to Examples 17.1 through 17.3 respectively. The “bo” is required for the same reason as in ✥16.2: to prevent the “ba” from functioning as a sumti tcita for the following sumti (or, in ✥17.5, from being attached to the following selbri).

In addition to the “bo” construction of Examples 17.4 through 17.6, there is also a form of tensed logical connective with “ke ... ke'e” (“tu'e... tu'u” for sentences). The logical connective system makes Examples 17.7 through 17.9 equivalent in meaning:

```✥17.7    mi bevri le dakli
.ije tu'e mi bevri le gerku
.ija mi bevri le mlatu tu'u
I carry the sack.
And (I carry the dog.
And/or I carry the cat).
I carry the sack. And I carry the dog, or I carry
the cat, or I carry both.

✥17.8 mi bevri le dakli
gi'eke bevri le gerku gi'a bevri le mlatu
I carry the sack
and (carry the dog and/or carry the cat).
I carry the sack, and also carry the dog
or carry the cat or carry both.

✥17.9 mi bevri le dakli .eke le gerku .a le mlatu
I carry the sack and (the dog or the cat)
I carry the sack and also the dog or the cat or both.```

Note the uniformity of the Lojban, as contrasted with the variety of ways in which the English provides for the correct grouping. In all cases, the meaning is that I carry the sack in any case, and either the cat or the dog or both.

To express that I carry the sack first (earlier in time), and then the dog or the cat or both simultaneously, I can insert tenses to form Examples 17.10 through 17.12:

```✥17.10  mi bevri le dakli
.ije ba tu'e mi bevri le gerku
.ijacabo mi bevri le mlatu tu'u
I carry the sack.
And [future] (I carry the dog.
And/or [present] I carry the cat.)
I carry the sack. And then I will carry the dog
or I will carry the cat or I will carry both
at once.```

```✥17.11  mi bevri le dakli
gi'ebake bevri le gerku
gi'acabo bevri le mlatu
I carry the sack
and [future] (carry the dog
and/or [present] carry the cat).
I carry the sack and then will carry the dog
or carry the cat or carry both at once.```

```✥17.12  mi bevri le dakli
.ebake bevri le gerku .acabo le mlatu
I carry the sack and
[future] (the cat and/or [present] the dog).
I carry the sack, and then the cat or the dog
or both at once.```

Examples 17.10 through 17.12 are equivalent in meaning to each other, and correspond to the tenseless Examples 17.7 through 17.9 respectively.