Partie intégrante de nos vies vs des recoins unexplored de leur imagination.

Pamela, 

As I am sure you know, generally in French it is the number of possessions that determine whether to use the plural possessive or not, but unsurprisingly there are some nuances/exceptions. 

Specifically, with the examples you have given : 

1. " Nos vies"  follows the general rule as expected - there are 2 or more people, each with one life giving 2 or more possessions - hence ' nos vies '. It would also be plural for ' nos imaginations '. 

2. " Leur imagination " - this is one of the areas where it gets tricky. 

In the plural 3rd person, the number of possessions that each person has is important. If there are several people, each with one of the 'possession', the singular form ' leur imagination/panier/voiture ' is used.

 If each person has more than 1 of the possession, the plural form is used. Hence, ' leurs voitures ' is possible. 

However, as each person only has 'one imagination' it can only be ' leur imagination', and the same holds for ' leur vie '. 

Have a read of the ' tricky part ' and the ' really tricky part ' in the attached from Laura Lawless. 

https://www.lawlessfrench.com/grammar/possessive-adjectives-plural-possessions/

HI Maarten,

Thanks for your reply. Have checked out the link you posted but am still a bit confused as we each have only one life and the artists have only one imagination. The situations seem to be similar but the use of singular vs plural is different. 

Pamela, 

It is a difficult topic to get to grips with !

A bit short on time ( my typing is very slow ) but unless someone beats me to it, will try to expand in the next day or two.

Pamela,

In the examples, the use of plural and singular nouns is exactly as in English - ' our lives ' as ' nos vies ', and ' their imagination ' as ' leur imagination '.

The question is why does this end up being the case here, when the ' standard' rule in French is multiple possessions means using plural possessive adjectives ?. ( As per link to lesson on this site below )

It is because the grammar of using ' leur ' or ' leurs ' is different. ( as per Laura Lawless site )

It is not enough with ' leur ' to just know whether there is only one possession, or more than one possession. The ' distribution ' of ownership is also important, because there are 2 situations in which the singular ' leur ' is used, as below. 

Singular leur is used when : 

1. ' they ' own only one thing between them - eg ' they' have one house - it is ' leur maison '. This is as expected.

2. ' they ' each separately own only one of the ' things ' - eg there are three people in the group and each one of the three has their own personal basket for collecting mushrooms -  ' leur panier '. 

These are not shared possessions of the ' group '- just as one's ' imagination ' is not shared. 

This is the main point of grammatical difference, and can really only be noticed in writing, or in speech when a vowel or h müet follows ' leur ' or ' leurs '. 

Having said that, this situation is not raised at all in many of the lessons, videos etc that I have seen on related topics, so I wouldn't sweat over it too much ! Laura Lawless describes this as ' idiomatic ' use.

(For completeness)

' Plural ' leurs ' is used as expected when 

1. ' They ' jointly own multiple things - eg there are 5 people in the group who jointly own 2 horses , it is ' leurs chevaux ' 

2. ' They ' each ' separately own more than 1 of the thing - eg there are 3 people in the group and two of them own 2 cars, the third one owns three cars - it is ' leurs voitures '.

 Notre/nos/votre/vos/leur/leurs = our/your/their (French Possessive Adjectives)

 https://www.lawlessfrench.com/grammar/possessive-adjectives-plural-possessors/

 https://www.lawlessfrench.com/grammar/possessive-adjectives-plural-possessions/