Is there any relation between inflation and unemployment? 

The Phillips Curve was a relationship among unemployment and inflation discovered by Professor A.W. Phillips. He found that there was a trade-off among unemployment and inflation, so that any attempt by governments to decrease unemployment was likely to lead to enhanced inflation. This relationship was seen by Keynesians as a justification of their policies. Though, in the 1970s the curve began to break down as the economy suffered from unemployment and inflation rising together (stagflation).