“…We recall that a two‐dimensional copula is a function C : [0, 1] 2 → [0, 1] satisfying the following conditions: - (1)For all x , y ∈ [0, 1], C ( x , 0) = C (0, y ) = 0.
- (2)For all x , y ∈ [0, 1], C ( x , 1) = x and C (1, y ) = y .
- (3)For all x 1 ≤ x 2 and y 1 ≤ y 2, we have
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