# Looking for a model architecture that can work with an unordered list of arbitrary length

I'm looking for a machine learning model architecture that takes in an arbitrary number of inputs and generates one output. Pretty much like GRU or LSTM, it's just that the order of the items in the input is irrelevant. So f([x1, x2, ..., xn])=y, where each x is of shape [i] while y is of shape [j] (not considering the batch dimension). And f([x1, x2, ..., xn])=f([xn, xn-1, ..., x1]) or any other order of the input. In other words, f treats its input as a set, unlike RNNs that treat their inputs as a list.

Is there such an architecture?