Special unions of unicoherent continua (Q2725465)

The main result of the paper says that if a Hausdorff continuum is the union of two unicoherent continua whose intersection is connected and locally connected, then it is unicoherent. For the metric case the result is well known and it has a relatively short proof. The paper shows a great difference in proving the result between the metric and the general case (for Hausdorff continua). The chapters are the following: 1. Introduction and first definitions. 2. Pseudogrills and \({\mathcal P}\)-decompositions. 3. \({\mathcal P}\)-unicoherence and chains. 4. An approximation technique. 5. Graph-theoretic tools. 6. Special unions of unicoherent continua.