Mr Nassan says that at the Tal Abyad border crossing on the Syrian-Turkish frontier, the Syrian side of which is held by Isis, the Turkish authorities have allowed wounded Isis fighters to seek medical help in Turkey.
With more confusion in the central sector, bordering India's northern state of Uttarakhand, there are in all a dozen stretches of frontier where neither side knows where even the disputed border should be.
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At the trial, held in mid-June, character witnesses testified that Dixon was "a harmless, inoffensive man, but destitute of business capacity" and "in reply to the question whether Dixon was non compos mentis, I consider him as being on the frontier line sometimes on one side, and sometimes on the other, just as the breeze of fortune happens to blow".
The Western Desert, inside the Egyptian frontier, separated the two sides on that front.
The so-called trigger line dividing Kurdish-controlled territory in the north from the rest of Iraq is more and more like a frontier defended on both sides by armed force.
By November, there was a continuous front line running from the North Sea to the Swiss frontier, occupied on both sides by armies in prepared defensive positions.
After nearly a year of discussions between the journal, the paper authors, and lawyers on both sides, Frontiers made it clear that they were unwilling to take the risk of publishing the paper and being open to potential frivolous lawsuits.
