PSTRUCT_CASES_TAC : thm_tactic
STRUCTURE
PairRules
LIBRARY
pair
SYNOPSIS
Performs very general structural case analysis.
DESCRIPTION
When it is applied to a theorem of the form: 
   th = A' |- ?p11...p1m. (x=t1) /\ (B11 /\ ... /\ B1k) \/ ... \/
                ?pn1...pnp. (x=tn) /\ (Bn1 /\ ... /\ Bnp)
in which there may be no paired existential quantifiers where a ‘vector’ of them is shown above, PSTRUCT_CASES_TAC th splits a goal A ?- s into n subgoals as follows: 
                             A ?- s
   ===============================================================
    A u {B11,...,B1k} ?- s[t1/x] ... A u {Bn1,...,Bnp} ?- s[tn/x]
that is, performs a case split over the possible constructions (the ti) of a term, providing as assumptions the given constraints, having split conjoined constraints into separate assumptions. Note that unless A' is a subset of A, this is an invalid tactic.
FAILURE
Fails unless the theorem has the above form, namely a conjunction of (possibly multiply paired existentially quantified) terms which assert the equality of the same variable x and the given terms.
USES
Generating a case split from the axioms specifying a structure.
SEEALSO
STRUCT_CASES_TAC
HOL  Kananaskis-14