x1 is the result of applying logical connective/conjunction x2 to the terms of the ordered list x3 in the order given, in system x4
x1 is not the truth value of the result, but the result itself. x2 is filled by a function or a la'e-prefixed quote of a connective (CON; JA*, JOI*). In Lojban, the terms of the ordered list in x3 need not syntactically match the connective used; for example, bridi tails can be used even when ja (as opposed to gi'e/gije) fills x2. The connective filling x2, if n-ary, will operate on the first n terms of the ordered list filling x3, then it will successively operate on the result and the next n-1 terms (after the previously used ones) of the ordered list in x3 where the the result and terms fill its argument slots in the order presented. Thus, the ordered list which fills x3 must be of an appropriate length; the recommendation is that exactly n terms are included; only explicitly mentioned terms are included. The terms of the ordered list in x3 and their results must be comparable; they can be sumti, bridi (la'e-prefixed quoted predicates; not its truth value), Booleans, sets, etc. This word can be used to express the notion of "logical conjunction", "logical disjunction", "set-theoretic union", "set-theoretic complement", etc. (the result, not the process, in each case); the terms of the list in x3 would be the conjunct(and)s (or their logical parents), etc. See: fancufacki, terjoma.