SAS 2020
Wed 18 - Fri 20 November 2020 Online Conference
co-located with SPLASH 2020
Thu 19 Nov 2020 21:40 - 22:00 at SPLASH-III - 6 Chair(s): Mihaela Sighireanu
Thu 19 Nov 2020 09:40 - 10:00 at SPLASH-III - 6 Chair(s): Mihaela Sighireanu

We consider the termination problem for triangular weakly non-linear loops (twn-loops) over some ring S like Z, Q, or R. Essentially, the guard of such a loop is an arbitrary Boolean formula over (possibly non-linear) polynomial inequations, and the body is a single assignment (x1,…,xd)⟵(c1⋅x1+p1,…,cd⋅xd+pd) where each xi is a variable, ci∈S, and each pi is a (possibly non-linear) polynomial over S and the variables xi+1,…,xd. We present a reduction from the question of termination to the existential fragment of the first-order theory of S and R. For loops over R, our reduction entails decidability of termination. For loops over Z and Q, it proves semi-decidability of non-termination. Furthermore, we present a transformation to convert certain non-twn-loops into twn-form. Then the original loop terminates iff the transformed loop terminates over a specific subset of R, which can also be checked via our reduction. This transformation also allows us to prove tight complexity bounds for the termination problem for two important classes of loops which can always be transformed into twn-loops.

Thu 19 Nov
Times are displayed in time zone: Central Time (US & Canada) change

09:00 - 10:00: 6SAS at SPLASH-III +12h
Chair(s): Mihaela SighireanuLSV, ENS Paris-Saclay
09:00 - 09:40
Talk
SAS
I: James WorrellUniversity of Oxford
File Attached
09:40 - 10:00
Research paper
SAS
Florian FrohnMax Planck Institute for Informatics, Marcel HarkRWTH Aachen University, Germany, Jürgen GieslRWTH Aachen University
Pre-print Media Attached File Attached
21:00 - 22:00: 6SAS at SPLASH-III
Chair(s): Mihaela SighireanuLSV, ENS Paris-Saclay
21:00 - 21:40
Talk
SAS
I: James WorrellUniversity of Oxford
File Attached
21:40 - 22:00
Research paper
SAS
Florian FrohnMax Planck Institute for Informatics, Marcel HarkRWTH Aachen University, Germany, Jürgen GieslRWTH Aachen University
Pre-print Media Attached File Attached