Mathematical "du" is not identity

[vpbroman]

In sections 18.5 and 18.7 and Example 18.39, and perhaps elsewhere, the explanation for the brivla "du" says that in mathematics "du" means equality, and in other contexts "du" means identity instead of equivalence. Unfortunately, mathematical or numerical equality is generally "dunli" equivalence and not "mintu" identity. In fact, as an aged applied mathematician, I cannot think of any mathematical usage (outside of computing and pointers) where we care that much about identity as opposed to equivalence. Note also that lojban brivla cannot have two meanings, dunli in math and mintu elsewhere.

While this change may require approval from an authoritative body, I recommend that the language standard define "du" as "dunli be fi zohe" except for allowing multiple right-hand-sides, and that the standard call it equivalence instead of identity.

After a quick scan of "The Wizard of Oz" I see that the translator used "du" in several places for "to be", meaning identity, so there is past usage we may not want to break, but "du" in mekso is central, and "du" instead of "mintu" in narrative is peripheral.

Also, the resemblance of "du" to "dunli" is probably intentional.

[lagleki]

@vpbroman what are the changes to the cll you may suggest?