Description and semantics of program graphs

Question

I'm working on a question which gives me a program graph and tells me to give a mathematical description of it. I'm aware that a program graph PG is a tuple

$(Loc, Act, Effect, \rightarrow, Loc_0, g_0)$

This is the question I'm trying to answer:

So far for $PG_1$ (one of the 2 transition systems) I have:

$Loc = \{k_1, k_2, k_3\},$ with $Loc_0 = \{k_1\}$

$Act = \{\alpha_1, \beta_1, \gamma_1\}$

$Effects = \{Effect(\alpha_1, \eta) = \eta[x := x + 1]$, $Effect(\beta_1, \eta) = \eta[y := y - 1]$, $Effect(\gamma_1, \eta = \eta[y := y + 2]\}$

$\rightarrow = \{(k_1, \alpha_1, k_2), (k_2, \beta_1, k_3), (k_3, \gamma_1, k_1)\}$

$g_0 = $ ?

I'm aware that $g_0$ is the starting condition, but I'm not sure what it is in this case? Also for $\rightarrow$ I assumed this was done the same was it is in Transition Systems, if somebody could clarify whether or not this is the correct way to do it I would be really grateful.

Thanks in advance for any help.