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We present VLA and ALMA observations of the close (0.3" = 90 au separation)protobinary system SVS 13. We detect two small circumstellar disks (radii$\sim$12 and $\sim$9 au in dust, and $\sim$30 au in gas) with masses of$\sim$0.004-0.009 $M_{sun}$ for VLA 4A (the western component) and$\sim$0.009-0.030 $M_{sun}$ for VLA 4B (the eastern component). A circumbinarydisk with prominent spiral arms extending $\sim$500 au and a mass of$\sim$0.052 $M_{sun}$ appears to be in the earliest stages of formation. Thedust emission is more compact and with a very high optical depth toward VLA 4B,while toward VLA 4A the dust column density is lower, allowing the detection ofstronger molecular transitions. We infer rotational temperatures of $\sim$140K, on scales of $\sim$30 au, across the whole source, and a rich chemistry.Molecular transitions typical of hot corinos are detected toward bothprotostars, being stronger toward VLA 4A, with several ethylene glycoltransitions detected only toward this source. There are clear velocitygradients, that we interpret in terms of infall plus rotation of thecircumbinary disk, and purely rotation of the circumstellar disk of VLA 4A. Wemeasured orbital proper motions and determined a total stellar mass of 1$M_{sun}$. From the molecular kinematics we infer the geometry and orientationof the system, and stellar masses of $\sim$0.26 $M_{sun}$ for VLA 4A and$\sim$0.60 $M_{sun}$ for VLA 4B.

The Physical Properties of the SVS 13 Protobinary System: Two Circumstellar Disks and a Spiraling Circumbinary Disk in the Making