x1 is a logical statement of proposition-equivalence/is a biconditional/'IFF' statement saying that x2 (du'u) is true if and only if x3 is true ("x2 is logically equivalent to x3; x2 being true is sufficient and necessary for guaranteeing the truth of x3; x2 iff x3").
x2 and x3 are mutually symmetric under exchange. This word is to jo as kanxe is to je. See also: kanxe, vlina, ribga, 3 is true if x2 is true; if x2, then x3; x2 being true is sufficient to guarantee the truth of x3").">sigda, jo.