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math.LO2023
Left absorption in products of countable orders
Garrett Ervin, Ethan Gu
We classify the countable linear orders for which there is an order with at least two points such that the lexicographic product is isomorphic to . Given such an $X…
math.LO2023
Decomposing the real line into everywhere isomorphic suborders
Garrett Ervin
We show that if is a partition of into two suborders and , then there is an open interval such that is not order-isomorph…
math.LO2018
Distinct orders dividing each other on both sides
Garrett Ervin
We construct non-isomorphic linear orders X and Y that are both left-hand and right-hand divisors of one another, answering positively a question of Sierpinski.
math.LO2016
Every linear order isomorphic to its cube is isomorphic to its square
Garrett Ervin
In 1958, Sierpinski asked whether there exists a linear order that is isomorphic to its lexicographically ordered cube but is not isomorphic to its square. The main result of t…