Consider a simple latch (two cross coupled inverters). The positive feedback makes the circuit operate in either of the two stable states if the overall gain is greater than unity. If there is a trigger that pushes the operating point beyond the switching point or pulls it down below the point, the output changes its state. Is the only difference between this and a schmitt trigger is that there are two trigger points in a schmitt trigger?
How do these circuits differ in operation in terms of positive feedback?