Suppose for my PhD thesis, I solve problems like the following:
1) At the begining I solve one problem
2) Later, before any one improve the results, I myself improve it.
Suppose both of the papaers get published. Will it still be considered as two different problems in thesis or just a single one ? Should one avoid to do such practice and try to put the best results only in thesis.
PS: By improving I mean earlier I solve some problem under some stronger assumption and later I weaken it.