The petitioners, together with respondents 3 and 4 and one K.Padmanabhan, had jointly put up a building on land that belonged to the said 3rd and 4th respondents and Sri.Padmanabhan. The building comprised of six residential apartments and, according to the petitioners, they had jointly contributed to the construction of the apartments in terms of Ext.P1 construction agreement that was entered into between them and the builder. It is their case that when the building came to be assessed for building tax, the assessment was completed against them by Ext.P3 order, by treating the entire building as one unit and not separate units for the purposes of assessment. Exts.P3 order, and Ext.P4 demand notice that was issued to the petitioners thereafter, were based on Ext.P2 order of the Tahsildar which, after taking note of the objections put forward by the petitioners, found that there was no material to justify a separate assessment of the individual apartments in the names of the owners of the said apartments. Thereafter, by Ext.P5 order, the petitioners were also assessed to luxury tax for the period from 2004-2005 to 2007-2008. In the writ petition, the petitioners have impugned Exts.P2, P3 and P5 orders and Ext.P4 demand notice. It is also submitted that they also