I am interested in knowing how we can use the concepts of Limits and Colimits in modeling problems in every day life? Could anyone provide (Software) engineering examples, perhaps? Or describe intuitively in general for what sorts of modeling problems we can use these concepts? (Providing even few examples will help in gaining an intuitive sense to generalize the application of the concepts in also other problems which may be of interest). Thank you.



What are the uses of Limits and Colimits of Category Theory in every day problems?
Here are some resources, not necessarily limited to limits and colimits:


1. Since you specifically ask about software engineering, perhaps you can loko at Steve Easterbrooks's slides "[An Introduction to Category Theory for Software Engineers](http://www.cs.toronto.edu/~sme/presentations/cat101.pdf)" (which I found by using Google, have you tried?). In particular I draw your attention to slide 18.
2. Databases and categories:


	* [Easik](http://mathcs.mta.ca/research/rosebrugh/Easik/) by Robert Rosebrugh et al. lets you derive schemata in a categorical way,
	and in particular it uses limits and colimits to express various constructions
	in databases.
	* Spivak and Wisnesky's [FQL](http://wisnesky.net/fql.html) is inspired by category theory also.
3. More generally look at David Spivak's work on [categories in informatics](http://math.mit.edu/~dspivak/informatics/).


Let me give just one concrete example: a join of two tables in a relational database is pullback, which is a categorical limit. In general, whenever we combine two specifications subject to sharing constraints, that is a pullback.


