Asymmetric and symmetric double bubbles in a ternary inhibitory system (Q2927870)

The authors considered a ternary system which was introduced in [Physica D 178, No. 1--2, 103--117 (2003; Zbl 1013.82029)] from \textit{H. Nakazawa} and \textit{T. Ohta}'s density functional formulation for triblock copolymers [``Microphase separation of ABC-type triblock copoymers'', Macromolecules, 26, 5503--5511 (1993)]. An interesting phenomenon in a ternary system in higher dimensions is arguably a triple junction. In two dimensions, a triple junction appears at points where interfaces separating some domains all come to meet. A double bubble is a typical structure of this property. The main result of the paper is about the existence of a double bubble under some conditions on the parameters of the system.