4K resolution
4K resolution, also called 4K, refers to a horizontal display resolution of approximately 4,000 pixels. Digital television and digital cinematography commonly use several different 4K resolutions. In television and consumer media, 38402160 (4K UHD) is the dominant 4K standard, whereas the movie projection industry uses 40962160 (DCI 4K).
4K resolution
Pixel shifting, as described here, was pioneered in the consumer space by JVC, and later in the commercial space by Epson. That said, it isn't the same thing as "true" 4K. More recently, some DLP projectors claim 4K UHD (which the JVCs and Epsons do not claim).