State territory — Parts of — Boundaries — Land boundaries — No established historical boundary line — Concept of a boundary belt — Recognition and acquiescence by territorial sovereign or suzerain state — Relinquishment of potential sovereign rights — Effect on successor states — Evidential value of maps — Acts in assertion of sovereignty — Exercise of jurisdiction in remote and uninhabited region — Relevance of acts of private individuals — Considerations of equity — Relevance of contiguity