+ *
+ * Recall that the procedure for implementing the insertion
+ * is outlined in section 6.2 of Abdulla et al. 2017 as follows:
+ *
+ * | Let `v` be the smallest (w.r.t to "<") sequence in [the tree] B
+ * | such that `v ~_[E] w`. If `v` is a leaf node, the tree can be left
+ * | unmodified.
+ * |
+ * | Otherwise let `w'` be the shortest sequence such that `w [=_[E] v.w'`
+ * | and add `v.w'` as a new leaf, ordered after all already existing nodes
+ * | of the form `v.w''`
+ *
+ * The procedure for determining whether `v ~_[E] w` is given as Lemma 4.6 of
+ * Abdulla et al. 2017:
+ *
+ * | The relation `v ~_[E] w` holds if either
+ * | (1) v = <>, or
+ * | (2) v := p.v' and either
+ * | (a) p in I_[E](w) and `v' ~_[E.p] (w \ p)`
+ * | (b) E ⊢ p ◊ w and `v' ~_[E.p] w`
+ *
+ * This method computes the result `v.w'` as needed (viz. only if `v ~_[E] w`
+ * with respect to this execution `E`). The implementation takes advantage
+ * of the fact that determining whether `v ~_[E] w` yields "for free" the
+ * the shortest such `w'` we are looking for; if we ultimately determine
+ * that `v ~_[E] w`, the work we did to do so leaves us precisely with `w'`,
+ * so we can simply prepend `v` to it and call it a day
+ *
+ * @precondition: This method assumes that `E.v` is a valid execution, viz.
+ * that the events of `E` are sufficient to enabled `v_0` and that
+ * `v_0, ..., v_{i - 1}` are sufficient to enable `v_i`. This is the
+ * case when e.g. `v := notdep(e, E).p` for example in ODPOR
+ *
+ * @returns a partial execution `v.w'` that should be inserted
+ * as a child of a wakeup tree node representing the sequence `v`
+ * if `v ~_[E] w`, or `std::nullopt` if that relation does not hold
+ * between the two sequences `v` and `w`