seeing as he said
If 2 miners start solo mining at the same time with the same hardware and firmware :
Suppose that they get the same work
"suppose they get the same work"
meaning he sent his friend the same block header details..
meaning both worked on same block. with same coinbase
then its technically not solomining but 2party pool mining
but as in my previous post i explained all the effects and after effects of friends wasted efforts and angers at doing this with both starting at the same nonce beginning