Continuous quivers of type A (I) The generalized barcode theorem.

We generalize type $A$ quivers to continuous type $A$ quivers and prove basic results about pointwise finite-dimensional representations. In particular, we generalize Crawley-Boevey's BarCode theorem to continuous quivers with alternating orientations: every pointwise finite-dimensional representation of a continuous type $A$ quiver is the direct sum of pointwise one-dimensional indecomposable whose supports are intervals. We also classify the indecomposable projective representations. This is part of a longer work in which we study a generalization of the continuous cluster category (introduced by the first and last author in 2015) and a continuous generalization of mutation.