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

2 years 21 weeksago2 years 30 weeksago2 years 31 weeksago3 years 8 weeksago3 years 29 weeksago