Here are two articles containing techniques for building examples with certain properties. The emphasis here is on the word "building": one specifically designs the examples to have the properties in question, and one builds them up step by step.

Tricki

a repository of mathematical know-how

4 years 31 weeksago4 years 39 weeksago4 years 40 weeksago5 years 18 weeksago5 years 38 weeksago