m4=k3 is a placebo [substance with no pharmacological effect] which patient m2=k1 believes/expects to cure ailment m3, placebo given by doctor/nurse m1.
x1 expects/looks for the occurence of x2 (event), expected likelihood x3 (0-1, default {li} {so'a} i.e. near 1); x1 subjectively evaluates the likelihood of x2 (event) to be x3.