Background: In science, posing problems is considered as important solving them, however, school has explored little this type of activity. Objective: To examine the features mathematical posed by elementary teachers, analysing aspects related to statement and types formulated. Design: Descriptive, qualitative research. Setting participants: Eighty-seven teachers (45 teaching 1st 2nd grades, 42...

This paper deals with ill-posed bilevel programs, i.e., problems admitting multiple lower-level solutions for some upper-level parameters. Many publications have been devoted to the standard optimistic case of this problem, where the difficulty is essentially moved from the objective function to the feasible set. This new problem is simpler but there is no guaranty to obtain local optimal solut...