This paper describes a simple means for embedding a checksum within a FITS header, providing a mechanism for later verifying the integrity of the FITS le. The method uses ASCII coded 32-bit 1's complement arithmetic to force the checksum of each FITS HDU to zero. This technique requires no extension of the FITS standard to be used by any given project, in fact the technique may be used to zero ...

The second author’s ω, ∆, χ conjecture proposes that every graph satisties χ ≤ d 1 2 (∆ + 1 + ω)e. In this paper we prove that the conjecture holds for all claw-free graphs. Our approach uses the structure theorem of Chudnovsky and Seymour. Along the way we discuss a stronger local conjecture, and prove that it holds for claw-free graphs with a three-colourable complement. To prove our results ...