## 10.9. Interval properties: TAhE and roi

The following cmavo are discussed in this section:

 di'i TAhE regularly na'o TAhE typically ru'i TAhE continuously ta'e TAhE habitually di'inai TAhE irregularly na'onai TAhE atypically ru'inai TAhE intermittently ta'enai TAhE contrary to habit roi ROI “n” times roinai ROI other than “n” times ze'e ZEhA whole time interval ve'e VEhA whole space interval

Consider Lojban bridi which express events taking place in time. Whether a very short interval (a point) or a long interval of time is involved, the event may not be spread consistently throughout that interval. Lojban can use the cmavo of selma'o TAhE to express the idea of continuous or non-continuous actions.

Example 10.40.

 mi puzu ze'u velckule I [past-long-distance] [long-interval] am-a-school-attendee (pupil).
 Long ago I attended school for a long time.

probably does not mean that I attended school continuously throughout the whole of that long-ago interval. Actually, I attended school every day, except for school holidays. More explicitly,

Example 10.41.

 mi puzu ze'u di'i velckule I [past-long-distance] [long-interval] [regularly] am-a-pupil.
 Long ago I regularly attended school for a long time.

The four TAhE cmavo are differentiated as follows: ru'i covers the entirety of the interval, di'i covers the parts of the interval which are systematically spaced subintervals; na'o covers part of the interval, but exactly which part is determined by context; ta'e covers part of the interval, selected with reference to the behavior of the actor (who often, but not always, appears in the x1 place of the bridi).

Using TAhE does not require being so specific. Either the time direction or the time interval or both may be omitted (in which case they are vague). For example:

Example 10.42.

 mi ba ta'e klama le zarci I [future] [habitually] go-to the market. I will habitually go to the market.
 I will make a habit of going to the market.

specifies the future, but the duration of the interval is indefinite. Similarly,

Example 10.43.

 mi na'o klama le zarci I [typically] go-to the market.
 I typically go/went/will go to the market.

illustrates an interval property in isolation. There are no distance or direction cmavo, so the point of time is vague; likewise, there is no interval cmavo, so the length of the interval during which these goings-to-the-market take place is also vague. As always, context will determine these vague values.

Intermittently is the polar opposite notion to continuously, and is expressed not with its own cmavo, but by adding the negation suffix -nai (which belongs to selma'o NAI) to ru'i. For example:

Example 10.44.

 le verba ru'inai cadzu le bisli The child [continuously-not] walks-on the ice.
 The child intermittently walks on the ice.

As shown in the cmavo table above, all the cmavo of TAhE may be negated with -nai; ru'inai and di'inai are probably the most useful.

An intermittent event can also be specified by counting the number of times during the interval that it takes place. The cmavo roi (which belongs to selma'o ROI) can be appended to a number to make a quantified tense. Quantified tenses are common in English, but not so commonly named: they are exemplified by the adverbs never, once, twice, thrice, ... always, and by the related phrases many times, a few times, too many times, and so on. All of these are handled in Lojban by a number plus -roi:

Example 10.45.

 mi paroi klama le zarci I [one-time] go-to the market.
 I go to the market once.

Example 10.46.

 mi du'eroi klama le zarci I [too-many-times] go-to the market.
 I go to the market too often.

With the quantified tense alone, we don't know whether the past, the present, or the future is intended, but of course the quantified tense need not stand alone:

Example 10.47.

 mi pu reroi klama le zarci I [past] [two-times] go-to the market.
 I went to the market twice.

The English is slightly over-specific here: it entails that both goings-to-the-market were in the past, which may or may not be true in the Lojban sentence, since the implied interval is vague. Therefore, the interval may start in the past but extend into the present or even the future.

Adding -nai to roi is also permitted, and has the meaning other than (the number specified):

Example 10.48.

 le ratcu reroinai citka le cirla The rat [twice-not] eats the cheese.
 The rat eats the cheese other than twice.

This may mean that the rat eats the cheese fewer times, or more times, or not at all.

It is necessary to be careful with sentences like Example 10.45 and Example 10.47, where a quantified tense appears without an interval. What Example 10.47 really says is that during an interval of unspecified size, at least part of which was set in the past, the event of my going to the market happened twice. The example says nothing about what happened outside that vague time interval. This is often less than we mean. If we want to nail down that I went to the market once and only once, we can use the cmavo ze'e which represents the whole time interval: conceptually, an interval which stretches from time's beginning to its end:

Example 10.49.

 mi ze'e paroi klama le zarci I [whole-interval] [once] go-to the market.

Since specifying no ZEhA leaves the interval vague, Example 10.47 might in appropriate context mean the same as Example 10.49 after all – but Example 10.49 allows us to be specific when specificity is necessary.

A PU cmavo following ze'e has a slightly different meaning from one that follows another ZEhA cmavo. The compound cmavo ze'epu signifies the interval stretching from the infinite past to the reference point (wherever the imaginary journey has taken you); ze'eba is the interval stretching from the reference point to the infinite future. The remaining form, ze'eca, makes specific the whole of time interpretation just given. These compound forms make it possible to assert that something has never happened without asserting that it never will.

Example 10.50.

 mi ze'epu noroi klama le zarci I [whole-interval-past] [never] go-to the market.
 I have never gone to the market.

says nothing about whether I might go in future.

The space equivalent of ze'e is ve'e, and it can be used in the same way with a quantified space tense: see Section 10.11 for an explanation of space interval modifiers.