A conjunction with similar meaning is aun cuando.There are a number of other ways of expressing concession in Spanish:por mucho que+ verb + subjunctive
por más+ noun (pl.) +que+ subjunctive
por muy+ adjective +que+ subjunctive
Por mucho que insistas, no voy a comprarte un helado.
However much you insist, I won’t buy you an ice cream.Por más libros que lea, no aprobará en matemáticas.
However many books he/she reads, he/she won’t pass mathematics.Por muy tonto que sea, debe comprender que no hay que
comportarse de tal manera.
However stupid he is, he must understand that one shouldn’t behave
like that.
Subjunctive+lo que+ subjunctive:Cueste lo que cueste, lo voy a comprar.
I’ll buy it, whatever it costs.
Sea como sea, no te quiero decir más.
Be that as it may, I’m telling you no more.
Subjunctive+o no (+ subjunctive)Tenga dinero o no (tenga dinero), lo va a comprar.
Whether he has any money or whether he doesn’t, he’s going to buy it.
See also si bien, which takes the same verb forms as si (18.2.4).Some conjunctions with a concessional meaning can be used to introduce the
statement of a fact; when they do, the indicative is used:Aunque llovía, salimos.
Even though it was raining we went out. (fact)Por mucho que insistía, no le compré un helado.
However much he/she insisted (= even though he/she insisted a lot),
I didn’t buy him/her an ice cream. (fact)
Aunque can also introduce an unreal condition, in which case it has the same verb
forms as si (see 18.2.4):Aunque estuviera aquí, no le hablaría.
Even if he/she were here, I wouldn’t talk to him/her. (he/she isn’t here)18.2.4 The subjunctive and indicative with si
^50 (p. 296);^51 (p. 299)
Si has a special syntax. It is used:- with the pluperfect subjunctive for unreal conditions (i.e. envisaging something
which was not the case) in the past.
The subjunctive after conjunctions 18.2