No, the relation shown in the arrow diagram below is not a function.
In Mathematics and Geometry, a function defines and represents the relationship that exists between two or more variables in a relation, table, ordered pair, or graph.
This ultimately implies that, a function is typically used in mathematics for uniquely mapping an input variable (Set P) to an output variable (Set Q).
Based on the mapping (arrow) diagram shown above, we can reasonably infer and logically deduce that the input {1.2} is a domain value that is mapped to multiple output values {6, 8}.
Complete Question;
Is the relation shown in the arrow diagram a function?