(a) A case shall be held to involve or to grow out of a labor dispute
when the case involves persons who are engaged in the same industry,
trade, craft or occupation; or who are employees of one employer; or who
are members of the same or an affiliated organization of employers or
employees; whether such dispute is between one or more employers or
associations of employers and one or more employees or associations of
employees; between one or more employers or associations of employers
and one or more employers or associations of employers; or between one
or more employees or associations of employees and one or more employees
or associations of employees; or when the case involves any conflicting
or competing interests in a "labor dispute" (as hereinafter defined) of
"persons participating or interested" therein (as hereinafter defined);
(b) The term "labor dispute" includes any controversy concerning terms
or conditions of employment, or concerning the association or
representation of persons in negotiating, fixing, maintaining, changing
or seeking to arrange terms or conditions of employment, or concerning
employment relations, or any other controversy arising out of the
respective interests of employer and employee, regardless of whether or
not the disputants stand in the relation of employer and employee;
(c) A person or association shall be held to be a person participating
or interested in a labor dispute if relief is sought against him or it
and if he or it is engaged in the industry, trade, craft, or occupation
in which such dispute occurs, or is a member, officer or agent of any
association of employers or employees engaged in such industry, trade,
craft, or occupation.