substack.native

[EUnder True (ESymbol Op "\8721") (EArray [AlignCenter] [[[EGrouped [ENumber "0",ESymbol Rel "<",EIdentifier "i",ESymbol Rel "<",EIdentifier "m"]]],[[EGrouped [ENumber "0",ESymbol Rel "<",EIdentifier "j",ESymbol Rel "<",EIdentifier "n"]]]]),EIdentifier "P",EDelimited "(" ")" [Right (EIdentifier "i"),Right (ESymbol Pun ","),Right (EIdentifier "j")]]