Synergies between Vera C. Rubin Observatory, Nancy Grace Roman Space
  Telescope, and Euclid Mission: Constraining Dark Energy with Type Ia
  Supernovae
  We review the needs of the supernova community for improvements in survey
coordination and data sharing that would significantly boost the constraints on
dark energy using samples of Type Ia supernovae from the Vera C. Rubin
Observatories, the \textit{Nancy Grace Roman Space Telescope}, and the
\textit{Euclid} Mission. We discuss improvements to both statistical and
systematic precision that the combination of observations from these
experiments will enable. For example, coordination will result in improved
photometric calibration, redshift measurements, as well as supernova distances.
We also discuss what teams and plans should be put in place now to start
preparing for these combined data sets. Specifically, we request coordinated
efforts in field selection and survey operations, photometric calibration,
spectroscopic follow-up, pixel-level processing, and computing. These efforts
will benefit not only experiments with Type Ia supernovae, but all time-domain
studies, and cosmology with multi-messenger astrophysics.
