In response to the following query on the Systemic Functional Linguistics Interest Group:
What kind of process is 'live' in the following sentence - We live in the same city. Is it relational??? Identifying circumstantial?
Not relational and there's conjecture whether it's material or behavioural. If you are a strict Hallidayan, it might be behavioural as only sensate beings can do behavioural processes whereas anything, sensate or non-sensate can do material processes. However, as a Martinian, behavioural clauses are those that seem like verbal and mental but can't project. Definitely NOT relational as relational relates one participant to another.
and on 23 June 2016:
[In the] example 'he is in the kitchen', 'in the kitchen' is not functioning as a circumstance in this instance, it's functioning as an Attribute. Circumstantial meanings are incredibly versatile and can move around the clause mapping onto all kinds of constituents … . And from above, living is NOT being. Though we could probably argue about that till the cows come home, … And I recall Fran Christie telling me that Michael Halliday told her that living and dying are material.
 The clause we live in the same city is an intensive attributive relational clause — as opposed to material — on several grounds.
Viewed from above, it means 'we are in the same city' rather than 'we do in the same city'. That is, in terms of the complementary perspectives of being-&-having and doing-&-happening, the construal is one of being.
Viewed from roundabout, the unmarked present tense is simple not the present-in-present, so relational not material. If it were material, the simple present tense would be marked because it would carry the added feature 'habitual'.
A 'behavioural' interpretation is ruled out by the definition of behavioural processes as physiological and psychological processes as behaviours. Halliday & Matthiessen (2004: 171):
On the borderline between ‘material’ and ‘mental’ are the behavioural processes: those that represent the outer manifestations of inner workings, the acting out of processes of consciousness and physiological states.
 To be 'a strict Hallidayan' is merely to understand and apply the theory that is the brainchild of Halliday; Cf 'a strict Einsteinian'.
antonyms: imprecise, loose
 This is not a criterion for distinguishing behavioural processes from material and relational processes. Conscious beings can participate in all process types.
 In matters of grammar, Martin purports to be following Halliday — e.g. Martin, Matthiessen & Painter (2010: i) — and so, any differences are misunderstandings, rather than competing interpretations. The treatment of behavioural processes in this work, Deploying Functional Grammar, is particularly confused, as demonstrated here. Moreover, contrary to Dreyfus' claim, Martin et al. (2010: 124) analyse some projecting clauses as behavioural.
 This is misleading in two ways. On the one hand, there are relational clauses with only one participant (Carrier). This occurs when a quality is construed as a qualitative Process (it matters) rather than as a qualitative Attribute (it is important); see Halliday & Matthiessen (2004: 222).
On the other hand, the prepositional phrases in the same city and in the kitchen serve as circumstantial Attributes; see Halliday & Matthiessen (2004: 240-1).
With regard to the participanthood of Attribute, Halliday & Matthiessen (2004: 123) write:
… the Attribute cannot be mapped onto the interpersonal rôle of Subject. This is because only participants in the clause can take modal responsibility, and the Attribute is only marginally, if at all, a participant.
 Hearsay is not argument, and in this case, it demonstrably misrepresents Halliday's view. The function of a verb (verbal group) depends on the clause in which it figures. The verb 'live' can serve as a material Process (he lives life to the max), as a relational Process (he lives in Japan), and as an existential Process (Elvis lives).