?? "tangent space" of AG theory t at model m .... ?? as group object in _vsp_ ??? ... object as model over d with iso to m at basepoint .... ?? addition of objects ?? ... ?? addition of morphisms ?? ...

?? "deformation cohomology" ... ???? ...

?? "quasicoherent artin-wraith glueing" ....

?? "serre subcategory / quotient category" .... ??? ......

?? "ext as higher hom" ... ??? ....

?? representing extension by cocycle ( ?? ...) .... ???? representing morphism between such extensions by (?? higher? ...) cochain (?? ....) .... ??? ....

kernel _and_ cokernel .... ??? "double spectrum" ??? .... ??? ....