So far our examples have been isolated mekso (it is legal to have a bare mekso as a sentence in Lojban) and equation bridi involving du. What about inequalities such as “x < 5” ? The answer is to use a bridi with an appropriate selbri, thus:
Here is a partial list of selbri useful in mathematical bridi:
du | x_{1} is identical to x_{2}, x_{3}, x_{4}, ... |
dunli | x_{1} is equal/congruent to x_{2} in/on property/quality/dimension/quantity x_{3} |
mleca | x_{1} is less than x_{2} |
zmadu | x_{1} is greater than x_{2} |
dubjavme'a | x_{1} is less than or equal to x_{2} [ du ja mleca , equal or less] |
dubjavmau | x_{1} is greater than or equal to x_{2} [ du ja zmadu , equal or greater] |
tamdu'i | x_{1} is similar to x_{2} [ tarmi dunli , shape-equal] |
turdu'i | x_{1} is isomorphic to x_{2} [ stura dunli , structure-equal] |
cmima | x_{1} is a member of set x_{2} |
gripau | x_{1} is a subset of set x_{2} [ girzu pagbu , set-part] |
na'ujbi | x_{1} is approximately equal to x_{2} [ namcu jibni , number-near] |
terci'e | x_{1} is a component with function x_{2} of system x_{3} |
Note the difference between dunli and du ; dunli has a third place that specifies the kind of equality that is meant. du refers to actual identity, and can have any number of places:
Lojban bridi can have only one predicate, so the du is not repeated.
Any of these selbri may usefully be prefixed with na , the contradictory negation cmavo, to indicate that the relation is false:
As usual in Lojban, negated bridi say what is false, and do not say anything about what might be true.