  We propose a strengthening of the conclusion in Tur\'an's (3,4)-conjecture in
terms of algebraic shifting, and show that its analogue for graphs does hold.
In another direction, we generalize the Mantel-Tur\'an theorem by weakening its
assumption: for any graph G on n vertices and any involution on its vertex set,
if for any 3-set S of the vertices, the number of edges in G spanned by S, plus
the number of edges in G spanned by the image of S under the involution, is at
least 2, then the number of edges in G is at least the Mantel-Tur\'an bound,
namely the number achieved by two disjoint cliques of sizes n/2 rounded up and
down.
