Emptiness in Theravada and Mahayana What is the difference between the concept of emptiness (Śūnyatā in Sanskrit, or suññatā in Pali) in the Theravada tradition and the concept of emptiness in the Mahayana tradition?

From my basic understanding, Theravada emptiness is only regarding the self, while Mahayana emptiness is regarding all things. Is this true?

Or does Theravada also teach the emptiness of all things (e.g. in the sutta about foam and bubbles)?

Are these (Theravada emptiness and Mahayana emptiness) really completely different, or at some level, do they allude to the same thing?

For Theravada, could it be, that the emptiness of self is important for the path to ending suffering, but the emptiness of all things is not important for the path to ending suffering (as per the Parable of the Poisoned Arrow and the Parable of the Leaves in the Forest)?

I found the following quote from this answer interesting:


  It is said that beginner practitioners ("hinayana") only understand
  corelessness of beings (anatta), but still assume various stuff to be
  objectively/ontologically existing. This results in them erroneously
  reifying such concepts as the five skandhas, 12 nidanas, 4 noble
  truths, nirvana, and enlightenment. Advanced practitioners
  ("mahayana") clearly understand that all knowable phenomena without
  exception are contextually defined composites.
The following answer is informed by Insight into Emptiness by Khensur Jampa Tegchok who was a former abbot of Sera Je Monastery.

Presentation of Tenets

According to what is currently taught in contemporary Tibetan Buddhist monasteries, the view of selflessness differs between proponents of the Fundamental Vehicle school (which includes Theravada) and the Universal Vehicle school (or Mahayana). The common delineation is given as four different (ancient) tenet systems regarding selflessness:


Vaibhashika
Sautrantika
Chittamatra
Madhyamaka


The first two tenet systems belong to members of the Fundamental Vehicle school while the latter two are ascribed to the Universal Vehicle.

Here is a brief breakdown of the view of selflessness as it differs among these tenet systems:

Selflessness of persons (from course to subtle)


Emptiness of a permanent, unitary, and independent person
Emptiness of a self-sufficient, substantially existent person
Emptiness of an inherently existent person


Selflessness of phenomena


Emptiness of existing by its own characteristics as the basis or
referent of its name
Emptiness of the form and so forth and a valid cognizer of it being
different substances (different substantial entities)
Emptiness of true existence (existing without being posited by the
force of appearing to a nondefective consciousness)
Emptiness of inherent existence (existing from its own side,
existing by its own characteristics, and so on)


Definitions:


Permanent means something that does not change from one moment to the next
Impermanent means that something changes under the influences of causes and conditions
Unitary is something that is one seamless whole that has no parts
Independent has different definitions given different contexts:


Independent is something not being affected by or not relying upon causes and conditions
In the context of a person it means being independent of the aggregates as well
In Prasangika it means existing without depending on being merely imputed by name and concept

Self-sufficient means being able to exist independently in a
self-supporting manner, without depending on anything else, such as
the aggregates
Substantially existent person means being able to know such a person
exists without the appearance of the aggregates


In general, it is said that the Fundamental Vehicle systems do not subscribe to the selflessness of phenomena. Furthermore, the Vaibhashikas only subscribe to the lack of a permanent, unitary and independent person. That is they do believe that a self-sufficient, substantially existent person exists. The Sautrantikas on the other hand do not believe in a self-sufficient, substantially existent person nor do any of the other tenet systems.

All of that is to say, it is my understanding that the modern day Theravada is most closely aligned with the Sautrantika tenet system.