Hello,

 

Can someone please explaine what is law of conservation of probablity in lay-man and mathamatical terms.

 

Thanks.

It depends a little on the context. In some simple cases it may just mean that the probabilities of all possible events has to add up to 1. In quantum mechanics you have a probability density when looking at a wave function, and there is a probability operator. Conservation means that the total probability doesn't change over time (it's related to continuity equations). If you have a non-interacting particle, you expect to have that particle some time later — the probability of finding it still has to be one. You have to have written your equations and operators to properly reflect this.

 

Here's some math