# How to specify and calculate conditional probabilities with trinomials?

Could someone give an example of a simple BN using trinomial nodes? I am a bit confused, particularly on how to specify and calculate conditional probabilities with trinomials.

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For the benefit of all, please edit your post to define any initialisms upon first use. – cardinal Dec 17 '11 at 23:45
Specifically, what the heck is a "BN"? Briefing Note? Binomial Number? Belief Network? Bayesian Network? – whuber Dec 18 '11 at 16:56