Intersecting Systems of Signed Sets
Intersecting Systems of Signed Sets
A family ${\cal F}$ of sets is said to be (strictly) EKR if no non-trivial intersecting sub-family of ${\cal F}$ is (as large as) larger than some trivial intersecting sub-family of ${\cal F}$. For a finite set $X := \{x_1, ..., x_{|X|}\}$ and an integer $k \geq 2$, we define …