Notes on “Bipolar fuzzy graphs”

In this note, we show by examples that Definitions 3.1, 5.6, and 5.7, Example 5.8, Propositions 5.9 and 5.10, and partial proof of Propositions 5.11 and 5.12 in a previous paper by Akram (Muhammad Akram, Bipolar fuzzy graphs, Inform. Sci. 181 (2011) 5548–5564) contain some flaws and then provide the correct versions. Finally, we introduce a generalized bipolar fuzzy graph.