ai no production requirments?

[trinitrotoluene]

in three seperate games i played i've noticed that the ai don't always have meet the requirments for what they want to build, such as being able to build a bank without a market or a university without a library or a swordsman without iron. is this suppost to happen on king difficulty or is it a bug that is never in favor of the human player?

 

[FeiLing]

Pretty sure they need a market for a bank and similar building dependencies. Just when you take over the city, sometimes the market might be destroyed while the bank survives the pillage.

Same for units. They will not build Swordsmen without Iron. Eventually they build them and then lost the Iron (trade expired, mine pillaged, city with iron lost) - if they got more Iron units on the field though than they actually have Iron now, you'll see it in a fights estimation where these iron units would get a penalty.
However I think it's more likely that they just used up all their iron on iron units, so to you it will be shown that he has no iron leftover.

 

[Camikaze]

Is it possible to sell your library once you've built a university (for instance)? I assume it is, and that might be another explanation (although what FeiLing suggests makes more sense).