This allows correct display of both valid and invalid UTF-8 pasted together. Another factor that can render a model invalid is human error. The values can be interpreted as dark/light, absent/present, locked/unlocked, valid/invalid, et cetera. Several studies have investigated the influence of valid and invalid cues. Posner devised a scheme of using valid and invalid cues across trials. It is defined as a deductive argument that is invalid. RE 37,516 has been declared invalid and unenforceable. Quiet NaNs are used to propagate errors resulting from invalid operations or values. Most crashes are the result of executing invalid machine instructions. The restrictive covenant was ruled contestable, though not inherently invalid. This "skin effect" renders the above equation invalid. The UN General Assembly approved a resolution declaring the vote illegal and invalid. The effect is to make the decision completely invalid. This illness hampered his productivity and rendered him an invalid. He was also found to be driving with an invalid licence.