Patrick Lühne
c294a29cb2
This adds support for declaring predicates as placeholders through the
“#external” directive in the input language of clingo.
Placeholders are not subject to completion. This prevents predicates
that represent instance-specific facts from being assumed as universally
false by default negation when translating an encoding.
This stretches clingo’s usual syntax a bit to make the implementation
lightweight. In order to declare a predicate with a specific arity as a
placeholder, the following statement needs to be added to the program:
#external <predicate name>(<arity>).
Multiple unit tests cover cases where placeholders are used or not as
well as a more complex graph coloring example.
anthem 
Translate answer set programs to first-order theorem prover language
Overview
anthem translates ASP programs (in the input language of clingo) to the language of first-order theorem provers such as Prover9.
Usage
$ anthem [--simplify] file...
With the option --simplify, output formulas are simplified by applying several basic transformation rules.
Building
anthem requires CMake for building.
After installing the dependencies, anthem is built with a C++17 compiler (GCC ≥ 7.3 or clang ≥ 5.0).
$ git clone https://github.com/potassco/anthem.git
$ cd anthem
$ git submodule update --init --recursive
$ mkdir -p build/release
$ cd build/release
$ cmake ../.. -DCMAKE_BUILD_TYPE=Release
$ make