kb.tell("(B11 <=> (P12 OR P21))");
kb.tell("(B21 <=> ((P11 OR P22) OR P31))");
kb.tell("(NOT B11)");
kb.tell("(B21)");
Model model = new Model();
model = model.extend(new Symbol("B11"), false);
model = model.extend(new Symbol("B21"), true);
model = model.extend(new Symbol("P11"), false);
model = model.extend(new Symbol("P12"), false);
model = model.extend(new Symbol("P21"), false);
model = model.extend(new Symbol("P22"), false);
model = model.extend(new Symbol("P31"), true);
Sentence kbs = kb.asSentence();
Assert.assertEquals(true, model.isTrue(kbs));
}