Preface
    The Alberto Mendelzon Workshop is an international scientific venue started
in 2006 to honor the memory of Alberto Mendelzon, who made a significant
contribution to the field of data management. It has been an established forum
for top-quality research on the foundations of data management. While focused
especially on Latin American students and scholars, the workshop is open to
submissions from around the world, and it has so far gathered some of the
world’s best researchers in the field.
    This volume contains papers accepted for the 12th edition of the AMW, held
in Cali, Colombia, from May 23 to 25, 2018. As in previous editions, the call for
papers of this edition solicited two types of submissions: regular and short pa-
pers, where the latter was intended to present ongoing research, results published
elsewhere, and applications. The workshop received 37 submissions from around
the globe. The vast majority of these submissions were of high quality and re-
ported on intriguing on-going or latest research development on diverse data
management topics. Following a rigorous reviewing effort, whereby each submis-
sion has been allocated at least three reviewers, the program committee accepted
29 papers to form an excellent workshop program with five sessions: data ana-
lytics, reasoning, query answering, and incomplete and probabilistic databases.
Each accepted paper has a presentation slot at the workshop and may appear
in the workshop proceedings. The paper presentations were accompanied by
four keynote sessions, featuring Miriam Fernandez (Open University, UK) on AI
for policing, Hung Q. Ngo (RelationalAI Inc, USA) on worst-case optimal join
algorithms, Pablo Barceló (University of Chile, Chile) on reverse engineering
problems for database query languages, and Vanessa Murdock (Amazon, USA)
on large-scale analysis of user engagement.
    As in previous editions, AMW 2018 hosted the Alberto Mendelzon Workshop
School (AMWS), which consists of four three-hour tutorials given by invited in-
ternational speakers. The school was held before AMW, on May 21 - 22, 2018.
This year’s tutorials were on: information visualization and visual analytics by
Denis Para (Pontificia Universidad Católica de Chile, Chile); mining social me-
dia data by Miriam Fernandez (Open University, UK); the Bitcoin protocol by
Martı́n Ugarte (Free University of Brussels, Belgium); and data quality by Fei
Chiang and Mostafa Milani (McMaster University, Canada).
    We would like to warmly thank: the authors of the submitted papers; the pre-
senters at the workshop; the keynote speakers; Juan Sequeda (Capsenta, USA),
the General Chair of AMW 2018; the fantastic and professional Program Com-
mittee; the AMW School Committee; the AMW Steering Committee; and the
local organizers and local supporting institutions. Without their effort, AMW
2018 would not have been successful. We are keenly looking forward to the next
editions of the Alberto Mendelzon Workshop!

                                                          Cali, May 2018
Dan Olteanu (University of Oxford, UK) and Barbara Poblete (University of
Chile, Chile), AMW 2018 Program Committee co-chairs