Set analysis not working

[gauravgg]

HI

I have the following expression

sum(

{<

[Quota.VALIDFROM]={">=$(=MonthStart(date(min([Cost_RLP.CalMonth_New]))))"}

,

[Quota.VALIDTO]={"<=$(=MonthEnd(date(min([Cost_RLP.CalMonth_New]))))"}

>}

[Quota./BIC/K_QUOTE] )

For all the date the date format are also same.

It is not working