DescriptionTamari lattice, trees.svg	The associahedron of order 4 (or K5), the Hasse diagram of the Tamari lattice of order 4, with binary trees The knots of the trees correspond to the 2-subsets.
Source	Own work
Author	Watchduck You can name the author as "T. Piesk", "Tilman Piesk" or "Watchduck".
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The associahedron K5 has C₄ = 14 vertices, 21 edges and T₄−1 = 9 faces.
Each one of the faces corresponds to a 2-subset of {1,2,3,4,5} except {1,5}. Faces whose 2-subsets overlap do not touch.
(Overlap would mean that an element in one set is between the elements of the other, like with {1,3} and {2,4}.)
An edge or vertex corresponds to a set that contains the 2-subsets of the faces that meet in this edge or vertex.

	Triangulated hexagons	Binary trees	Sets of 2-subsets	Ovals	Parentheses
Vertices (and edges)
Faces