Planet Formation Imager (PFI): science vision and key requirements

Stefan Kraus, John D. Monnier, Michael J. Ireland, Gaspard Duchêne, Catherine Espaillat, Sebastian Hönig, Attila Juhasz, Chris Mordasini, Johan Olofsson, Claudia Paladini, Keivan Stassun, Neal Turner, Gautam Vasisht, Tim J. Harries, Matthew R. Bate, Jean-François Gonzalez, Alexis Matter, Zhaohuan Zhu, Olja Panic, Zsolt Regaly, Alessandro Morbidelli, Farzana Meru, Sebastian Wolf, John Ilee, Jean-Philippe Berger, Ming Zhao, Quentin Kral, Andreas Morlok, Amy Bonsor, David Ciardi, Stephen R. Kane, Kaitlin Kratter, Greg Laughlin, Joshua Pepper, Sean Raymond, Lucas Labadie, Richard P. Nelson, Gerd Weigelt, Theo ten Brummelaar, Arnaud Pierens, Rene Oudmaijer, Wilhelm Kley, Benjamin Pope, Eric L.~N. Jensen, Amelia Bayo, Michael Smith, Tabetha Boyajian, Luis Henry Quiroga-Nuñez, Rafael Millan-Gabet, Andrea Chiavassa, Alexandre Gallenne, Mark Reynolds, Willem-Jan de Wit, Markus Wittkowski, Florentin Millour, Poshak Gandhi, Cristina Ramos Almeida, Almudena Alonso Herrero, Chris Packham, Makoto Kishimoto, Konrad R.~W. Tristram, Jörg-Uwe Pott, Jean Surdej, David Buscher, Chris Haniff, Sylvestre Lacour, Romain Petrov, Steve Ridgway, Peter Tuthill, Gerard van Belle, Phil Armitage, Clement Baruteau, Myriam Benisty, Bertram Bitsch, Sijme-Jan Paardekooper, Christophe Pinte, Frederic Masset, Giovanni Rosotti