Assertion: graph's g | /r/HasAspect | zero
Facets:
value: in the region
type: LOCATION
value: for planar graphs
type: OTHER
Source sentences:
text: When Birkhoff and Lewis introduced the chromatic polynomial in their attack on the four-color theorem, they conjectured that for planar graphs G, the polynomial P ( G , t ) {\displaystyle P(G,t)} has no zeros in the region [ 4 , ∞ )