/// <summary>
/// Add constraints to ensure the function f can only be injective.
/// Example:
/// for function f : D1 x D2 -> R
/// assert axioms
/// forall (x1 : D1, x2 : D2) x1 = inv1(f(x1,x2))
/// forall (x1 : D1, x2 : D2) x2 = inv2(f(x1,x2))
/// </summary>
/// <param name="f"></param>
public void AssertInjective(Z3_func_decl f)
{
uint arity = Native.Z3_get_arity(nCtx, f);
Z3_sort range = Native.Z3_get_range(nCtx, f);
Z3_ast[] vars = new Z3_ast[arity];
Z3_sort[] sorts = new Z3_sort[arity];
Z3_symbol[] names = new Z3_symbol[arity];
for (uint i = 0; i < arity; ++i)
{
Z3_sort domain = Native.Z3_get_domain(nCtx, f, i);
vars[i] = ntvContext.MkBound(arity - i - 1, domain);
sorts[i] = domain;
names[i] = Native.Z3_mk_int_symbol(nCtx, (int)i);
}
Z3_ast app_f = IntPtr.Zero; // Context.MkApp(f, vars);
for (uint i = 0; i < arity; ++i)
{
Z3_sort domain = Native.Z3_get_domain(nCtx, f, i);
Z3_func_decl proj = ntvContext.MkFreshFuncDecl("inv", new Z3_sort[] { range }, domain);
Z3_ast body = ntvContext.MkEq(vars[i], ntvContext.MkApp(proj, app_f));
Z3_ast q = ntvContext.MkForall(names, sorts, body);
Assert(q);
}
}
/// <summary>
/// Create a new tuple sort.
/// </summary>
public Z3_sort MkTupleSort(Z3_symbol name, Z3_symbol[] fieldNames, Z3_sort[] fieldSorts, out Z3_func_decl constructor, Z3_func_decl[] projections)
{
Debug.Assert(name != IntPtr.Zero);
Debug.Assert(fieldNames != null);
Debug.Assert(fieldNames.All(fn => fn != IntPtr.Zero));
Debug.Assert(fieldSorts == null || fieldSorts.All(fs => fs != IntPtr.Zero));
var numFields = (uint)(fieldNames?.Length ?? 0);
constructor = IntPtr.Zero;
return(Native.Z3_mk_tuple_sort(nCtx, name, numFields, fieldNames, fieldSorts, ref constructor, projections));
}