% two communicating vessels; induced by Hylke's code
struct_rel(self, X, X) :-
	has_quantity(X, _X).

model([
	dependency(inf_pos, flow3, amount5),
	dependency(inf_neg, flow3, amount4),
	dependency(prop_neg, flow3, pressure5), 
	dependency(prop_pos, flow3, pressure4),
	dependency(prop_pos, height4, amount4),
	dependency(prop_pos, height5, amount5),
	dependency(prop_pos, pressure5, height5),
	dependency(prop_pos, pressure4, height4),
	dependency(q_correspondence, height5, amount5),
	dependency(q_correspondence, pressure4, height4),
	dependency(q_correspondence, pressure5, height5),
	dependency(q_correspondence, height4, amount4),
	dependency(equals, flow3, min(pressure4, pressure5)),
	%NB: the following two were not induced:
	dependency(equals, height4, pressure4),	
	dependency(equals, height5, pressure5)
]).

% isa(generic, instance)
isa(pipe, pipe1).
isa(container, container_left).
isa(container, container_right).

isa(flow, flow3).
isa(amount, amount4).
isa(amount, amount5).
isa(height, height4).
isa(height, height5).
isa(pressure, pressure4).
isa(pressure, pressure5).

struct_rel(from, container_left, pipe1).
struct_rel(to, pipe1, container_right).

% quantity(Entity, Quantity). one to many relation between instances
has_quantity(pipe1, flow3).
has_quantity(container_left, amount4).
has_quantity(container_left, height4).
has_quantity(container_left, pressure4).
has_quantity(container_right, amount5).
has_quantity(container_right, height5).
has_quantity(container_right, pressure5).