10.20. Logical and non-logical connections between tenses

Like many things in Lojban, tenses may be logically connected; logical connection is explained in more detail in Chapter 14. Some of the terminology in this section will be clear only if you already understand logical connectives.

The appropriate logical connectives belong to selma'o JA. A logical connective between tenses can always be expanded to one between sentences:

Example 10.152. 

mi pu je ba klama le zarci
I [past] and [future] go-to the market.

I went and will go to the market.

means the same as:

Example 10.153. 

mi pu klama le zarci
I [past] go-to the market.
.ije mi ba klama le zarci
And I [future] go-to the market.

I went to the market, and I will go to the market.

Tense connection and tense negation are combined in:

Example 10.154. 

mi punai je canai je ba klama le zarci
I [past-not] and [present-not] and [future] go-to the market.

I haven't yet gone to the market, but I will in future.

Example 10.154 is far more specific than

Example 10.155. 

mi ba klama le zarci
I [future] go-to the market.

which only says that I will go, without claiming anything about my past or present. ba does not imply punai or canai; to compel that interpretation, either a logical connection or a ZAhO is needed.

Tense negation can often be removed in favor of negation in the logical connective itself. The following examples are equivalent in meaning:

Example 10.156. 

mi mo'izu'anai je mo'iri'u cadzu
I [motion-left-not] and [motion-right] walk.

I walk not leftward but rightward.

Example 10.157. 

mi mo'izu'a naje mo'iri'u cadzu
I [motion-left] not-and [motion-right] walk.

I walk not leftward but rightward.

There are no forethought logical connections between tenses allowed by the grammar, to keep tenses simpler. Nor is there any way to override simple left-grouping of the connectives, the Lojban default.

The non-logical connectives of selma'o JOI, BIhI, and GAhO are also permitted between tenses. One application is to specify intervals not by size, but by their end-points (bi'o belongs to selma'o BIhI, and connects the end-points of an ordered interval, like English from ... to):

Example 10.158. 

mi puza bi'o bazu vasxu
I [past-medium] from…to [future-long] breathe.

I breathe from a medium time ago till a long time to come.

(It is to be hoped that I have a long life ahead of me.)

One additional use of non-logical connectives within tenses is discussed in Section 10.21. Other uses will probably be identified in future.