What is Israel that we recognize?

I came across an interesting article in the LATimes - "In the war of words, The Times is Israel's ally". Although the article is focusing on media biases, what attracted my attention was a question about the notion of recognizing Israel. Here is that part:

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Second, which Israel, precisely, are the Palestinians being asked to "recognize?" Israel has stubbornly refused to declare its own borders. So, territorially speaking, "Israel" is an open-ended concept. Are the Palestinians to recognize the Israel that ends at the lines proposed by the 1947 U.N. Partition Plan? Or the one that extends to the 1949 Armistice Line (the de facto border that resulted from the 1948 war)? Or does Israel include the West Bank and East Jerusalem, which it has occupied in violation of international law for 40 years — and which maps in its school textbooks show as part of "Israel"?
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I am so quite surprised to know this is not clear!!!